Add Python3 antelope unit tests
Add Python3 antelope unit tests

This is an automatically generated patch to ensure unit testing
is in place for all the of the tested runtimes for antelope.

See also the PTI in governance [1].

[1]: https://governance.openstack.org/tc/reference/project-testing-interface.html

Change-Id: Ida38facc856fd53162da9cd6e59eab1c10ab889f

openstack/oslo.utils