Merge pull request #1 from Niek/add-arm64

Add arm64 image

Author: pimterry

.github/workflows/ci.yml

@@ -34,6 +34,7 @@ jobs:
       - uses: docker/build-push-action@v2
         with:
           push: ${{ github.event_name != 'pull_request' }}
+          platforms: linux/amd64,linux/arm64
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}