ci: build and push for arm64 and arm/v7 archs

.github/workflows/dockerhub.yml

@@ -62,7 +62,7 @@ jobs:
         uses: docker/build-push-action@v2
         with:
           file: Dockerfile
-          platforms: linux/amd64
+          platforms: linux/amd64,linux/arm64,linux/arm/v7
           push: true
           tags: |
             ${{ github.ref != 'refs/heads/master' && steps.docker_meta_debian.outputs.tags || '' }}
@@ -74,7 +74,7 @@ jobs:
         uses: docker/build-push-action@v2
         with:
           file: Dockerfile.alpine
-          platforms: linux/amd64
+          platforms: linux/amd64,linux/arm64,linux/arm/v7
           push: true
           tags: |
             ${{ github.ref != 'refs/heads/master' && steps.docker_meta_alpine.outputs.tags || '' }}