This container can be pulled via:
  docker pull registry.opensuse.org/devel/kubic/containers/container_arm/opensuse/postfix:3.5.8
  docker pull registry.opensuse.org/devel/kubic/containers/container_arm/opensuse/postfix:3.5.8-15.28
  docker pull registry.opensuse.org/devel/kubic/containers/container_arm/opensuse/postfix:latest

Set DOCKER_CONTENT_TRUST=1 to enable image tag verification.