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

Build failed. https://zuul.opendev.org/t/openstack/buildset/020e7d5c5d9f4448a22fc66abd512f... - openstack-tox-docs https://zuul.opendev.org/t/openstack/build/e4ac95f9f03d4c238eb1492f3183d4ad : SUCCESS in 4m 56s - openstack-tox-py27 https://zuul.opendev.org/t/openstack/build/33ac31e8aa404ed4b9eead466d7bbead : FAILURE in 2m 29s - openstack-tox-py36 https://zuul.opendev.org/t/openstack/build/72df1cfe33844c5fa0d85f898d2b2e47 : SUCCESS in 3m 00s - openstack-tox-py37 https://zuul.opendev.org/t/openstack/build/19fe59357a464dd2995785d94964926e : SUCCESS in 4m 43s