This container can be pulled via:
  docker pull registry.opensuse.org/home/dcassany/elemental/containers/elemental3ctl-sysext:0_1.2-1.3
  docker pull registry.opensuse.org/home/dcassany/elemental/containers/elemental3ctl-sysext:latest

Set DOCKER_CONTENT_TRUST=1 to enable image tag verification.