Switch testing to Victoria testing runtime

Upating the testing template from ussuri to victoria
testing runtime
- https://governance.openstack.org/tc/reference/runtimes/victoria.html

Change-Id: Id8c5862b59188f2607c45392fa3b01b681825488

.zuul.yaml

@@ -1,6 +1,6 @@
 - project:
     templates:
       - openstack-cover-jobs
-      - openstack-python3-ussuri-jobs
+      - openstack-python3-victoria-jobs
       - release-notes-jobs-python3
       - publish-openstack-docs-pti

setup.cfg

@@ -19,6 +19,7 @@ classifier =
     Programming Language :: Python :: 3
     Programming Language :: Python :: 3.6
     Programming Language :: Python :: 3.7
+    Programming Language :: Python :: 3.8
 
 [files]
 packages =

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 minversion = 3.1.1
-envlist = py{37,36},pep8,pip-check-reqs
+envlist = py{38,36},pep8,pip-check-reqs
 skipsdist = True
 ignore_basepython_conflict = True