This container can be pulled via:
  docker pull registry.opensuse.org/opensuse/alertmanager:0.32
  docker pull registry.opensuse.org/opensuse/alertmanager:0.32.1
  docker pull registry.opensuse.org/opensuse/alertmanager:0.32.1-38.123
  docker pull registry.opensuse.org/opensuse/alertmanager:latest

Set DOCKER_CONTENT_TRUST=1 to enable image tag verification.