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

Build failed. https://zuul.opendev.org/t/openstack/buildset/96ab0f247f6d4601a6b5a5e8fc33e6... - openstack-tox-docs https://zuul.opendev.org/t/openstack/build/fcaf9974977a4ac6ad7dd344fbaba611 : SUCCESS in 3m 50s - openstack-tox-py27 https://zuul.opendev.org/t/openstack/build/e26f267d4bda48c3bf495d071bf60f92 : SUCCESS in 2m 37s - openstack-tox-py36 https://zuul.opendev.org/t/openstack/build/f776c1048cb14d6d917b090f3f16ad8e : SUCCESS in 4m 19s - openstack-tox-py37 https://zuul.opendev.org/t/openstack/build/a7b3f0931c5b4a70971e1ee463a3969d : FAILURE in 4m 22s