chore: Set permissions for GitHub actions

 Restrict the GitHub token permissions only to the required ones; this way, even if the attackers will succeed in compromising your workflow, they won’t be able to do much.

- Included permissions for the action. https://github.com/ossf/scorecard/blob/main/docs/checks.md#token-permissions

https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions#permissions

https://docs.github.com/en/actions/using-jobs/assigning-permissions-to-jobs

[Keeping your GitHub Actions and workflows secure Part 1: Preventing pwn requests](https://securitylab.github.com/research/github-actions-preventing-pwn-requests/)

Signed-off-by: neilnaveen <[email protected]>

.github/workflows/ci.yaml

@@ -7,6 +7,9 @@ on:
 env:
   GOPATH: ${{ github.workspace }}/go
 
+permissions:
+  contents: read
+
 jobs:
   test-and-verify:
     runs-on: ubuntu-latest

.github/workflows/pr.yaml

@@ -1,5 +1,11 @@
+permissions:
+  contents: read
+
 jobs:
   changes:
+    permissions:
+      contents: read  # for dorny/paths-filter to fetch a list of changed files
+      pull-requests: read  # for dorny/paths-filter to read pull requests
     outputs:
       charts: ${{ steps.filter.outputs.charts }}
     runs-on: ubuntu-latest

.github/workflows/release.yaml

@@ -1,5 +1,10 @@
+permissions:
+  contents: read
+
 jobs:
   release:
+    permissions:
+      contents: write  # for helm/chart-releaser-action to push chart release and create a release
     runs-on: ubuntu-latest
     steps:
       - name: Checkout