This container can be pulled via:
  docker pull registry.opensuse.org/systemsmanagement/cobbler/github-ci/containers/cobbler-test-github:suma-head
  docker pull registry.opensuse.org/systemsmanagement/cobbler/github-ci/containers/cobbler-test-github:suma-head.3.1

Set DOCKER_CONTENT_TRUST=1 to enable image tag verification.