add back in linux/s390x

Author: cbaker6

.github/workflows/docker-publish.yml

@@ -52,7 +52,7 @@ jobs:
         uses: docker/build-push-action@v2
         with:
           context: .
-          platforms: linux/amd64, linux/arm/v6, linux/arm/v7, linux/arm64/v8, linux/ppc64le
+          platforms: linux/amd64, linux/arm/v6, linux/arm/v7, linux/arm64/v8, linux/ppc64le, linux/s390x
           push: ${{ github.event_name != 'pull_request' }}
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}