Add workflow to build dotty-ci

.github/workflows/dotty-ci-container.yaml

@@ -0,0 +1,68 @@
+name: Build & Deploy the CI image for Dotty
+on:
+    ## Trigger this workflow when a change is detected in the Dockerfile
+    ## or in the following file
+    push:
+        branches:
+            - main
+        paths:
+            - .github/Dockerfile
+            - .github/workflows/dotty-ci-container.yaml
+    pull_request:
+        paths:
+          - .github/Dockerfile
+          - .github/workflows/dotty-ci-container.yaml
+
+concurrency:
+  group: dotty-ci-build
+  cancel-in-progress: false
+
+permissions:
+  contents: read
+  packages: write
+
+env:
+  ##REGISTRY: ghcr.io
+  IMAGE_NAME: ${{ github.repository }}/dotty-ci
+
+jobs:
+    build_and_deploy:
+        runs-on: ubuntu-latest
+        steps:
+            - name: Checkout the repository
+              uses: actions/checkout@v4
+            - uses: docker/setup-buildx-action@v3
+            #- name: Log in to the registry
+            #  uses: docker/login-action@v3
+            #  with:
+            #    registry: ${{ env.REGISTRY }}
+            #    username: ${{ github.actor }}
+            #    password: ${{ secrets.GITHUB_TOKEN }}
+            - name: Extract metadata for the image
+              uses: docker/metadata-action@v5
+              id: metadata
+              with:
+                images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+                ## TODO: Should we use the short SHA instead?
+                tags: |
+                  type=schedule,pattern={{date 'YYYY-MM-DD'}}
+          ## Build when triggered by a pull_request
+            - name: Build the image
+              uses: docker/build-push-action@v5
+              if: github.event_name == 'pull_request'
+              with:
+                context: .github
+                push: false
+                tags: ${{ steps.metadata.outputs.tags }}
+                labels: ${{ steps.metadata.outputs.labels }}
+                platforms: linux/amd64
+          ## Build and push when triggered by a push to the default branch
+            - name: Build and push the image
+              uses: docker/build-push-action@v5
+              if: github.event_name == 'push'
+              with:
+                context: .github
+                push: true
+                tags: ${{ steps.metadata.outputs.tags }}
+                labels: ${{ steps.metadata.outputs.labels }}
+                platforms: linux/amd64