This container can be pulled via:
  docker pull registry.opensuse.org/opensuse/spamassassin:4.0.1
  docker pull registry.opensuse.org/opensuse/spamassassin:4.0.1-6.137
  docker pull registry.opensuse.org/opensuse/spamassassin:latest

Set DOCKER_CONTENT_TRUST=1 to enable image tag verification.