* Use self update ready entrypoint
* Add --once support for runsvc.sh
Run `cd runner; NAME=$DOCKER_USER/actions-runner TAG=dev make docker-build docker-push`,
`kubectl apply -f release/actions-runner-controller.yaml`,
then update the runner image(not the controller image) by updating e.g. `Runner.Spec.Image` to `$DOCKER_USER/actions-runner:$TAG`, for testing.
Co-authored-by: Yusuke Kuoka <ykuoka@gmail.com>