tox: Ignore virtualenvs for pep8 environment

Change-Id: I473d1b6c1287325566a5f5f5aadaea802c6af6f4
Signed-off-by: Stephen Finucane <sfinucan@redhat.com>

Author: stephenfin

tox.ini

@@ -133,7 +133,7 @@ commands =
 show-source = True
 # H203: Use assertIs(Not)None to check for None
 enable-extensions = H203
-exclude = .git,.tox,dist,doc,*lib/python*,*egg,build,tools
+exclude = .venv,.git,.tox,dist,doc,*lib/python*,*egg,build,tools,releasenotes
 # W504 is disabled since you must choose between this or W503
 ignore = W504
 import-order-style = pep8