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

Build failed. https://zuul.opendev.org/t/openstack/buildset/65657142321a46e98a39d735b1a0f4... - openstack-tox-docs https://zuul.opendev.org/t/openstack/build/6629b41742ac4c54b9d58844d2858ef9 : SUCCESS in 4m 09s - openstack-tox-py27 https://zuul.opendev.org/t/openstack/build/8dee13dabcf94dcd99365bd8a847715c : SUCCESS in 4m 33s - openstack-tox-py36 https://zuul.opendev.org/t/openstack/build/90cdeffe0cb84f6b97dde5f4ea623988 : SUCCESS in 4m 41s - openstack-tox-py37 https://zuul.opendev.org/t/openstack/build/977c6ce587ea4b1389ef192e89b00b3e : FAILURE in 3m 53s