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

Build failed.

- openstack-tox-docs https://zuul.opendev.org/t/openstack/build/4bc19e36eeca4e0f86a6b1d909da95ef : SUCCESS in 5m 43s - openstack-tox-py27 https://zuul.opendev.org/t/openstack/build/6e787ae2baea40ebb175f3f157ab1f41 : SUCCESS in 4m 50s - openstack-tox-py36 https://zuul.opendev.org/t/openstack/build/c5740de66e4d422cadb91cbf2d8f1127 : FAILURE in 5m 49s - openstack-tox-py37 https://zuul.opendev.org/t/openstack/build/38501f9c480b465d8215912105baa8f6 : SUCCESS in 8m 01s