This container can be pulled via:
  docker pull registry.opensuse.org/devel/kubic/containers/container/opensuse/squid:6.12
  docker pull registry.opensuse.org/devel/kubic/containers/container/opensuse/squid:6.12-12.240
  docker pull registry.opensuse.org/devel/kubic/containers/container/opensuse/squid:latest

Set DOCKER_CONTENT_TRUST=1 to enable image tag verification.