Add arm/v7 image builds

.github/workflows/docker-publish.yml

@@ -19,6 +19,7 @@ env:
   # github.repository as <account>/<repo>
   IMAGE_NAME: ${{ github.repository }}
 
+# Based partly on https://dev.to/cloudx/multi-arch-docker-images-the-easy-way-with-github-actions-4k54 without semver (for now)
 
 jobs:
   build:
@@ -44,9 +45,13 @@ jobs:
           cosign-release: 'v1.13.1'
 
 
-      # Workaround: https://github.com/docker/build-push-action/issues/461
-      - name: Setup Docker buildx
-        uses: docker/setup-buildx-action@79abd3f86f79a9d68a23c75a09a9a85889262adf
+      # https://github.com/docker/setup-qemu-action
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v1
+      # https://github.com/docker/setup-buildx-action
+      - name: Set up Docker Buildx
+        id: buildx
+        uses: docker/setup-buildx-action@v1
 
       # Login against a Docker registry except on PR
       # https://github.com/docker/login-action
@@ -73,6 +78,7 @@ jobs:
         uses: docker/build-push-action@ac9327eae2b366085ac7f6a2d02df8aa8ead720a
         with:
           context: .
+          platforms: linux/amd64,linux/arm/v7
           push: ${{ github.event_name != 'pull_request' }}
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}