This container can be pulled via:
  docker pull registry.opensuse.org/devel/bci/sle-15-sp6/containerfile/bci/gcc:7
  docker pull registry.opensuse.org/devel/bci/sle-15-sp6/containerfile/bci/gcc:7-56.1
  docker pull registry.opensuse.org/devel/bci/sle-15-sp6/containerfile/bci/gcc:7.5
  docker pull registry.opensuse.org/devel/bci/sle-15-sp6/containerfile/bci/gcc:7.5-56.1

Set DOCKER_CONTENT_TRUST=1 to enable image tag verification.