Update linting

Author: nicoddemus

tox.ini

@@ -15,11 +15,10 @@ commands =
     pytest test_pytest_mock.py --assert=plain -ra
 
 [testenv:linting]
-skip_install=True
 deps =
     pytest-flakes
     restructuredtext_lint
     pygments
 commands =
-    py.test --flakes pytest_mock.py test_pytest_mock.py -m flakes
+    pytest --flakes pytest_mock.py test_pytest_mock.py -m flakes
     rst-lint CHANGELOG.rst README.rst