Run flake8 in linters

We should run flake8 when we run the other checks. This
repo is mostly python.

Change-Id: I3cbecf9ef24f784c072841656b55c4162673dcaa

tox.ini

@@ -35,6 +35,7 @@ commands =
 passenv = *
 commands =
     {[testenv:build]commands}
+    {[testenv:pep8]commands}
     /bin/bash -c "ansible-galaxy collection install $(ls {toxinidir}/build_artifact/openstack-cloud-*) --force -p {toxinidir}"
     /bin/bash -c "cd ansible_collections/openstack/cloud && ansible-test sanity"
 
@@ -52,7 +53,7 @@ commands = {posargs}
 #      modules unchanged and then clean them in subsequent patches.
 ignore = W503,H4,E501,E402,H301,H236,F401,E128,W504,F841,F403,F405
 show-source = True
-exclude=.venv,.git,.tox,dist,doc,*lib/python*,*egg,build
+exclude=.venv,.git,.tox,dist,doc,*lib/python*,*egg,build,ansible_collections
 
 [testenv:ansible-new]
 # Need to pass some env vars for the Ansible playbooks