[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/75ca1a03974c4e1a9101d09e0c8fda... - openstack-tox-docs https://zuul.opendev.org/t/openstack/build/11da3b41992d4b5590be67241a21994f : SUCCESS in 4m 27s - openstack-tox-py27 https://zuul.opendev.org/t/openstack/build/3d2d6da025c74ebf851a95b4cc886299 : SUCCESS in 5m 26s - openstack-tox-py36 https://zuul.opendev.org/t/openstack/build/58717293f1eb4bd88f9aaa4603aa4d80 : SUCCESS in 4m 23s - openstack-tox-py37 https://zuul.opendev.org/t/openstack/build/bbc706234e8446b38b69420ad8877e9b : FAILURE in 4m 17s