[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/1cb09408e6d54a1bbc5d92ac996d5f... - openstack-tox-docs https://zuul.opendev.org/t/openstack/build/c86cc99ef90c4276a9e559b787a90de5 : SUCCESS in 5m 06s - openstack-tox-py27 https://zuul.opendev.org/t/openstack/build/9b95fc5cb05e4a7b94891838ea277bf9 : SUCCESS in 4m 21s - openstack-tox-py36 https://zuul.opendev.org/t/openstack/build/d4a3ca0fdb894a0d9bb24e3ccc6a178c : SUCCESS in 4m 03s - openstack-tox-py37 https://zuul.opendev.org/t/openstack/build/60af804d0d2b43b8b71cf9780ad9a9b4 : FAILURE in 3m 34s