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: I57d4d50a8bcd2a9a0a9af4fe37a184aa1085b75c

openstack/oslo.middleware