This container can be pulled via:
  docker pull registry.opensuse.org/isv/rancher/elemental/pr/rancher/elemental-operator/pr-561/containers/rancher/seedimage-builder:1.1.0
  docker pull registry.opensuse.org/isv/rancher/elemental/pr/rancher/elemental-operator/pr-561/containers/rancher/seedimage-builder:1.1.0-56.3
  docker pull registry.opensuse.org/isv/rancher/elemental/pr/rancher/elemental-operator/pr-561/containers/rancher/seedimage-builder:latest

Set DOCKER_CONTENT_TRUST=1 to enable image tag verification.