This container can be pulled via:
  docker pull registry.opensuse.org/isv/rancher/elemental/devgit/containers/suse/sl-micro/6.0/rt-iso-image:2.2.0-dev
  docker pull registry.opensuse.org/isv/rancher/elemental/devgit/containers/suse/sl-micro/6.0/rt-iso-image:2.2.0-dev-5.1
  docker pull registry.opensuse.org/isv/rancher/elemental/devgit/containers/suse/sl-micro/6.0/rt-iso-image:latest

Set DOCKER_CONTENT_TRUST=1 to enable image tag verification.