fix filter

Author: abbrowne126

pytest.ini

@@ -23,4 +23,4 @@ filterwarnings =
     # Remove once we move off credential files https://github.com/googleapis/google-auth-library-python/pull/1812
     # Note that these are used in tests only
     ignore:Your config file at [/home/kbuilder/.docker/config.json] contains these credential helper entries:DeprecationWarning
-    ignore:DeprecationWarning: The `credentials_file` argument is deprecated because of a potential security risk
+    ignore:The `credentials_file` argument is deprecated because of a potential security risk:DeprecationWarning