This container can be pulled via:
  docker pull registry.opensuse.org/opensuse/alertmanager:0.29
  docker pull registry.opensuse.org/opensuse/alertmanager:0.29.0
  docker pull registry.opensuse.org/opensuse/alertmanager:0.29.0-36.57
  docker pull registry.opensuse.org/opensuse/alertmanager:latest

Set DOCKER_CONTENT_TRUST=1 to enable image tag verification.