This container can be pulled via:
  docker pull registry.opensuse.org/home/dirkmueller/bci/cr/sle-15-sp5/containerfile/suse/alertmanager:0.26.0
  docker pull registry.opensuse.org/home/dirkmueller/bci/cr/sle-15-sp5/containerfile/suse/alertmanager:0.26.0-1.142
  docker pull registry.opensuse.org/home/dirkmueller/bci/cr/sle-15-sp5/containerfile/suse/alertmanager:latest

Set DOCKER_CONTENT_TRUST=1 to enable image tag verification.