ci(docker.yml): support `linux/arm64` container

.github/workflows/docker.yml

@@ -38,7 +38,7 @@ jobs:
         uses: docker/build-push-action@v5
         with:
           context: .
-          platforms: linux/amd64
+          platforms: linux/amd64,linux/arm64
           push: ${{ github.event_name != 'pull_request' }}
           tags: ${{ steps.metal.outputs.tags }}
           labels: ${{ steps.metal.outputs.labels }}