This container can be pulled via:
  docker pull registry.opensuse.org/devel/bci/sle-15-sp7/containerfile/bci/ruby:2
  docker pull registry.opensuse.org/devel/bci/sle-15-sp7/containerfile/bci/ruby:2.5
  docker pull registry.opensuse.org/devel/bci/sle-15-sp7/containerfile/bci/ruby:2.5-53.7

Set DOCKER_CONTENT_TRUST=1 to enable image tag verification.