Add Python3 wallaby unit tests
Add Python3 wallaby unit tests

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

See also the PTI in governance [1].

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

Change-Id: I48c38bb9d2d1812672dcc08e6e280efca3013d63

openstack/oslo.cache,openstack/oslo.cache