github: add CAA bot

We need external contributors to assign us copyright for the submitted
work, in case we want to update the materials license. This process is
currently performed manually, with the result stored in our internal git
server.

Use CLA Assistant lite to automate this part. The automation brings the
following components:
- a dedicated github action running each time a PR is opened or edited
- a proper CAA text for individuals and entities
- a file containing the list of individuals or entities who signed the CAA

Signed-off-by: Alexis Lothoré <[email protected]>

.github/workflows/caa.yml

@@ -0,0 +1,42 @@
+name: "CLA Assistant"
+on:
+  issue_comment:
+    types: [created]
+  pull_request_target:
+    types: [opened,closed,synchronize]
+
+permissions:
+  actions: write
+  contents: write
+  pull-requests: write
+  statuses: write
+
+jobs:
+  CLAAssistant:
+    runs-on: ubuntu-latest
+    steps:
+      - name: "CLA Assistant"
+        if: (github.event.comment.body == 'recheck' || github.event.comment.body == 'I have read the CLA Document and I hereby sign the CLA') || github.event_name == 'pull_request_target'
+        uses: contributor-assistant/[email protected]
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          PERSONAL_ACCESS_TOKEN: ${{ secrets.PERSONAL_ACCESS_TOKEN }}
+        with:
+          path-to-signatures: 'caa/signatures/signatures.json'
+          path-to-document: 'https://github.com/bootlin/training-materials/blob/master/caa/individual-caa.md' # e.g. a CLA or a DCO document
+          branch: 'master'
+          custom-notsigned-prcomment: >
+            Thank you for your contribution to Bootlin training materials !
+            Before being able to integrate those changes, we would like you to
+            sign our [Individual Contributor Assignment
+            Agreement](https://github.com/bootlin/training-materials/blob/master/caa/individual-caa.md)
+            if you are an individual, or our [Entity Contributor Assignment
+            Agreement](https://github.com/bootlin/training-materials/blob/master/caa/entity-caa.md)
+            if you are submitting this work on behalf of an entity.
+
+            You will still be credited for your contribution, but we would like
+            to keep the ability to switch to a different license for these
+            materials, or to give a license exception to a customer funding
+            some improvements or customization. You can sign the CLA by just
+            posting a Pull Request Comment with the sentence below. Thanks !
+

caa/entity-caa.md

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+# Bootlin Training Materials Entity Contributor Assignment Agreement
+
+Thank you for your interest in contributing to Bootlin ("We" or "Us") training
+materials.
+
+This contributor agreement ("Agreement") documents the rights granted by
+contributors to Us. To make this document effective, please sign it by following
+the instructions which led you to this document. This is a legally binding
+document, so please read it carefully before agreeing to it. The Agreement may
+cover more than one software project managed by Us.
+
+1. Definitions
+
+"You" means any Legal Entity on behalf of whom a Contribution has been received
+by Us. "Legal Entity" means an entity which is not a natural person.
+"Affiliates" means other Legal Entities that control, are controlled by, or
+under common control with that Legal Entity. For the purposes of this
+definition, "control" means (i) the power, direct or indirect, to cause the
+direction or management of such Legal Entity, whether by contract or otherwise,
+(ii) ownership of fifty percent (50%) or more of the outstanding shares or
+securities which vote to elect the management or other persons who direct such
+Legal Entity or (iii) beneficial ownership of such entity.
+
+"Contribution" means any work of authorship that is Submitted by You to Us in
+which You own or assert ownership of the Copyright. If You do not own the
+Copyright in the entire work of authorship, please follow the instructions in
+Section 3, point d.
+
+"Copyright" means all rights protecting works of authorship owned or controlled
+by You or Your Affiliates, including copyright, moral and neighboring rights, as
+appropriate, for the full term of their existence including any extensions by
+You.
+
+"Material" means the work of authorship which is made available by Us to third
+parties. When this Agreement covers more than one software project, the Material
+means the work of authorship to which the Contribution was Submitted. After You
+Submit the Contribution, it may be included in the Material.
+
+"Submit"  means any form of electronic, verbal, or written communication sent to
+Us or our representatives, including but not limited to electronic mailing
+lists, source code control systems, and issue tracking systems that are managed
+by, or on behalf of, Us for the purpose of discussing and improving the
+Material, but excluding communication that is conspicuously marked or otherwise
+designated in writing by You as "Not a Contribution."
+
+"Submission Date" means the date on which You Submit a Contribution to Us.
+
+"Effective Date" means the date You execute this Agreement or the date You first
+Submit a Contribution to Us, whichever is earlier.
+
+"Media" means any portion of a Contribution which is not software. 
+
+
+2. Grant of Rights
+
+2.1 Copyright Assignment
+
+(a) At the time the Contribution is Submitted, You assign to Us all right,
+title, and interest worldwide in all Copyright covering the Contribution;
+provided that this transfer is conditioned upon compliance with Section 2.3.
+
+(b) To the extent that any of the rights in Section 2.1(a) cannot be assigned by
+You to Us, You grant to Us a perpetual, worldwide, exclusive, royalty-free,
+transferable, irrevocable license under such non-assigned rights, with rights to
+sublicense through multiple tiers of sublicensees, to practice such non-assigned
+rights, including, but not limited to, the right to reproduce, modify, display,
+perform and distribute the Contribution; provided that this license is
+conditioned upon compliance with Section 2.3.
+
+(c) To the extent that any of the rights in Section 2.1(a) can neither be
+assigned nor licensed by You to Us, You irrevocably waive and agree never to
+assert such rights against Us, any of our successors in interest, or any of our
+licensees, either direct or indirect; provided that this agreement not to assert
+is conditioned upon compliance with Section 2.3.
+
+(d) Upon such transfer of rights to Us, to the maximum extent possible, We
+immediately grant to You a perpetual, worldwide, non-exclusive, royalty-free,
+transferable, irrevocable license under such rights covering the Contribution,
+with rights to sublicense through multiple tiers of sublicensees, to reproduce,
+modify, display, perform, and distribute the Contribution. The intention of the
+parties is that this license will be as broad as possible and to provide You
+with rights as similar as possible to the owner of the rights that You
+transferred. This license back is limited to the Contribution and does not
+provide any rights to the Material.
+
+2.2 Patent License
+
+For patent claims including, without limitation, method, process, and apparatus
+claims which You [or Your Affiliates] own, control or have the right to grant,
+now or in the future, You grant to Us a perpetual, worldwide, non-exclusive,
+transferable, royalty-free, irrevocable patent license, with the right to
+sublicense these rights to multiple tiers of sublicensees, to make, have made,
+use, sell, offer for sale, import and otherwise transfer the Contribution and
+the Contribution in combination with the Material (and portions of such
+combination). This license is granted only to the extent that the exercise of
+the licensed rights infringes such patent claims; and provided that this license
+is conditioned upon compliance with Section 2.3.
+
+2.3 Outbound License
+
+Based on the grant of rights in Sections 2.1 and 2.2, if We include Your
+Contribution in a Material, We may license the Contribution under any license,
+including copyleft, permissive, commercial, or proprietary licenses. As a
+condition on the exercise of this right, We agree to also license the
+Contribution under the terms of the license or licenses which We are using for
+the Material on the Submission Date.
+
+2.4 Moral Rights. If moral rights apply to the Contribution, to the maximum
+extent permitted by law, You waive and agree not to assert such moral rights
+against Us or our successors in interest, or any of our licensees, either direct
+or indirect.
+
+2.5 Our Rights. You acknowledge that We are not obligated to use Your
+Contribution as part of the Material and may decide to include any Contribution
+We consider appropriate.
+
+2.6 Reservation of Rights. Any rights not expressly assigned or licensed under
+this section are expressly reserved by You.
+
+3. Agreement
+
+You confirm that:
+
+(a) You have the legal authority to enter into this Agreement.
+
+(b) You or Your Affiliates own the Copyright and patent claims covering the
+Contribution which are required to grant the rights under Section 2.  
+
+(c) The grant of rights under Section 2 does not violate any grant of rights
+which You or Your Affiliates have made to third parties.
+
+(d) If You do not own the Copyright for the entire work submitted, You have
+stated this fact in your submission, made aware all the corresponding Copyright
+Owners, and all those Copyright Owners have signed the Contributor Assignment
+Agreeement as well.
+
+4. Disclaimer
+
+EXCEPT FOR THE EXPRESS WARRANTIES IN SECTION 3, THE CONTRIBUTION IS PROVIDED "AS
+IS". MORE PARTICULARLY, ALL EXPRESS OR IMPLIED WARRANTIES INCLUDING, WITHOUT
+LIMITATION, ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+PURPOSE AND NON-INFRINGEMENT ARE EXPRESSLY DISCLAIMED BY YOU TO US AND BY US TO
+YOU. TO THE EXTENT THAT ANY SUCH WARRANTIES CANNOT BE DISCLAIMED, SUCH WARRANTY
+IS LIMITED IN DURATION TO THE MINIMUM PERIOD PERMITTED BY LAW.
+
+5. Consequential Damage Waiver
+
+TO THE MAXIMUM EXTENT PERMITTED BY APPLICABLE LAW, IN NO EVENT WILL YOU OR US BE
+LIABLE FOR ANY LOSS OF PROFITS, LOSS OF ANTICIPATED SAVINGS, LOSS OF DATA,
+INDIRECT, SPECIAL, INCIDENTAL, CONSEQUENTIAL AND EXEMPLARY DAMAGES ARISING OUT
+OF THIS AGREEMENT REGARDLESS OF THE LEGAL OR EQUITABLE THEORY (CONTRACT, TORT OR
+OTHERWISE) UPON WHICH THE CLAIM IS BASED.
+
+6. Miscellaneous
+
+6.1 This Agreement will be governed by and construed in accordance with the
+laws of France excluding its conflicts of law provisions. Under certain
+circumstances, the governing law in this section might be superseded by the
+United Nations Convention on Contracts for the International Sale of Goods
+("UN Convention") and the parties intend to avoid the application of the UN
+Convention to this Agreement and, thus, exclude the application of the UN
+Convention in its entirety to this Agreement.
+
+6.2 This Agreement sets out the entire agreement between You and Us for
+Your Contributions to Us and overrides all other agreements or
+understandings.
+
+6.3  If You or We assign the rights or obligations received through this
+Agreement to a third party, as a condition of the assignment, that third
+party must agree in writing to abide by all the rights and obligations in
+the Agreement.
+
+6.4 The failure of either party to require performance by the other party
+of any provision of this Agreement in one situation shall not affect the
+right of a party to require such performance at any time in the future. A
+waiver of performance under a provision in one situation shall not be
+considered a waiver of the performance of the provision in the future or a
+waiver of the provision in its entirety.
+
+6.5 If any provision of this Agreement is found void and unenforceable,
+such provision will be replaced to the extent possible with a provision
+that comes closest to the meaning of the original provision and which is
+enforceable.  The terms and conditions set forth in this Agreement shall
+apply notwithstanding any failure of essential purpose of this Agreement or
+any limited remedy to the maximum extent possible under law.
+