Add ARM v7 architecture to Docker images (#741)

.github/workflows/docker-publish.yml

@@ -102,7 +102,7 @@ jobs:
         with:
           context: .
           file: ${{ matrix.dockerfile }}
-          platforms: linux/amd64,linux/arm64
+          platforms: linux/amd64,linux/arm64,linux/arm/v7
           push: ${{ github.event_name != 'pull_request' }}
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}