[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/6ac54e98e8e242b8ab8ce01f7b79d1... - openstack-tox-docs https://zuul.opendev.org/t/openstack/build/3e9e92840b994c5ea8b29afdde53215e : SUCCESS in 3m 41s - openstack-tox-py27 https://zuul.opendev.org/t/openstack/build/4af4f19a89df48899fc6608855bc17be : SUCCESS in 3m 17s - openstack-tox-py36 https://zuul.opendev.org/t/openstack/build/20732d7413ad4833a3516f2515c78efe : SUCCESS in 3m 17s - openstack-tox-py37 https://zuul.opendev.org/t/openstack/build/097a7a8861a1449b8136a48cfed4dfce : FAILURE in 4m 48s