This container can be pulled via:
  docker pull registry.opensuse.org/opensuse/leap/15.4/images/totest/containers/opensuse/leap-microdnf:15.4
  docker pull registry.opensuse.org/opensuse/leap/15.4/images/totest/containers/opensuse/leap-microdnf:15.4.3.776

Set DOCKER_CONTENT_TRUST=1 to enable image tag verification.