Build both linux/amd64 and linux/arm64 images

Author: jake-low

.github/workflows/docker-publish.yaml

@@ -50,6 +50,7 @@ jobs:
       with:
         context: .
         push: true
+        platforms: linux/amd64,linux/arm64
         tags: ${{ steps.meta.outputs.tags }}
         labels: ${{ steps.meta.outputs.labels }}
         cache-from: type=gha