This container can be pulled via:
  docker pull registry.opensuse.org/home/defolos/bci/cr/sle-15-sp7/containerfile/bci/spack:0.21
  docker pull registry.opensuse.org/home/defolos/bci/cr/sle-15-sp7/containerfile/bci/spack:0.21-8.3
  docker pull registry.opensuse.org/home/defolos/bci/cr/sle-15-sp7/containerfile/bci/spack:0.21.2

Set DOCKER_CONTENT_TRUST=1 to enable image tag verification.