This container can be pulled via:
  docker pull registry.opensuse.org/devel/kubic/containers/container/kubic/etcd:3.5.12-0.6.58
  docker pull registry.opensuse.org/devel/kubic/containers/container/kubic/etcd:3.5.12-1.6.58

Set DOCKER_CONTENT_TRUST=1 to enable image tag verification.