This container can be pulled via:
  docker pull registry.opensuse.org/kubic/etcd:3.5.15
  docker pull registry.opensuse.org/kubic/etcd:3.5.15-0
  docker pull registry.opensuse.org/kubic/etcd:3.5.15-0.8.68
  docker pull registry.opensuse.org/kubic/etcd:3.5.15-1
  docker pull registry.opensuse.org/kubic/etcd:3.5.15-1.8.68

Set DOCKER_CONTENT_TRUST=1 to enable image tag verification.