[Openstack-stable-maint] Stable check of openstack/castellan for ref refs/heads/stable/ussuri failed

Build failed. https://zuul.opendev.org/t/openstack/buildset/df3e8a9a2b0a442082e378405fbac3... - openstack-tox-docs https://zuul.opendev.org/t/openstack/build/8445d9b944e74f348be42bab98955381 : POST_FAILURE in 6m 35s - openstack-tox-py36 https://zuul.opendev.org/t/openstack/build/ec3fcf351afa423c8c1aaaca7e084d92 : SUCCESS in 3m 33s - openstack-tox-py37 https://zuul.opendev.org/t/openstack/build/decad8d32d204ec2a93284d14b092c9f : SUCCESS in 5m 22s