ci: publish to GitHub Container Registry (#2165)

.github/workflows/release.yml

@@ -28,15 +28,16 @@ jobs:
       - name: Compute tags
         id: tags
         run: |
-          DOCKER_IMAGE=public.ecr.aws/s2n/s2n-quic-qns
+          ECR_IMAGE=public.ecr.aws/s2n/s2n-quic-qns
+          GHCR_IMAGE=ghcr.io/aws/s2n-quic/s2n-quic-qns
           VERSION=main
           if [[ $GITHUB_REF == refs/tags/* ]]; then
             VERSION=${GITHUB_REF#refs/tags/v}
           fi
-          TAGS="${DOCKER_IMAGE}:${VERSION}"
+          TAGS="${ECR_IMAGE}:${VERSION},${GHCR_IMAGE}:${VERSION}"
           # mark the latest on release
           if [[ $VERSION =~ ^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$ ]]; then
-            TAGS="$TAGS,${DOCKER_IMAGE}:latest"
+            TAGS="$TAGS,${ECR_IMAGE}:latest,${GHCR_IMAGE}:latest"
           fi
           echo "tags=${TAGS}" >> $GITHUB_OUTPUT
 
@@ -48,6 +49,14 @@ jobs:
           username: ${{ secrets.AWS_ACCESS_KEY_ID }}
           password: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
 
+      - name: Login to GitHub Container Registry
+        uses: docker/login-action@v3.1.0
+        if: github.event_name == 'push' || github.repository == github.event.pull_request.head.repo.full_name
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
       - name: Build and push image
         uses: docker/build-push-action@v5
         with: