Prevent the publishing of an unknown arch package

Without this change, a second package with arch "unknown/unknown" will
be published to the package repository.

See docker/build-push-action#820 for more
information.

.github/workflows/github_release_docker.yml

@@ -69,6 +69,12 @@ jobs:
           context: .
           file: Dockerfile.prod
           push: ${{ github.ref_type == 'tag' }}
+          # This is required or a package with unknown architecture will be published too.
+          # See https://github.com/docker/build-push-action/issues/820 for further
+          # details.
+          # TODO - investigate further and see if we can find a solution where we
+          # don't have to set this.
+          provenance: false
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}
           cache-from: type=gha