Tweak Action for our environment

Author: Ed Kingscote

.github/workflows/release.yml

@@ -140,9 +140,6 @@ jobs:
         uses: docker/build-push-action@v2
         with:
           builder: ${{ steps.buildx.outputs.name }}
-          context: ./app
-          file: ./app/Dockerfile
-          target: prod
           platforms: linux/386,linux/amd64,linux/arm/v6,linux/arm/v7,linux/arm64,linux/ppc64le,linux/s390x
           push: ${{ github.event_name != 'pull_request' }}
           tags: ${{ steps.prep.outputs.tags }}