In #306 we seem to have accidentally updated a wrong workflow, which was for runner builds. This updates the one for the controller. Resolves #302
Deprecated action `crazy-max/setup-buildx-action@v1` has been replaced with: `docker/setup-qemu-action@v1` `docker/setup-buildx-action@v1` `docker/login-action@v1` `docker/build-push-action@v2` See: https://github.com/crazy-max/ghaction-docker-buildx
Fixes #135