Don't error on pkg-resources deprecation warning

Author: domdfcoding

tox.ini

@@ -233,6 +233,7 @@ filterwarnings =
     ignore:can't resolve package from __spec__ or __package__, falling back on __name__ and __path__:ImportWarning
     always:The \(fspath.*\) argument to YamlTestFile is deprecated:pytest.PytestRemovedIn8Warning
     always:module 'sre_constants' is deprecated:DeprecationWarning
+    always:pkg_resources is deprecated as an API:DeprecationWarning
 
 [doc8]
 ignore-path = doc-source/build