Publish arm64 image (#5)

Author: fwilhe

.github/workflows/build-postgres-container.yml

@@ -22,6 +22,8 @@ jobs:
 
     - name: Set up Docker Buildx
       uses: docker/setup-buildx-action@v3
+      with:
+        platforms: linux/amd64,linux/arm64
 
     - name: Docker meta
       id: meta
@@ -49,7 +51,7 @@ jobs:
       if: ${{ github.event_name != 'pull_request' }}
       uses: docker/build-push-action@v5
       with:
-        platforms: linux/amd64
+        platforms: linux/amd64,linux/arm64
         file: Containerfile
         push: true
         tags: ${{ steps.meta.outputs.tags }}