Add Python3 wallaby unit tests
Add Python3 wallaby unit tests

Ensure unit testing is in place for all the of the tested
runtimes for wallaby.

Copied from an automatically generated patch in the neutron
repo, don't know why the release bot missed it here.

See also the PTI in governance [1].

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

Change-Id: I7b415b97caa0be9cfd33f8f43a79e8fcdabfd3b3

openstack/kuryr,openstack/kuryr