Remove more Python 2 compatibility code

Author: jaraco

conftest.py

@@ -1,22 +1,13 @@
 import getpass
 import os
 
-import six
-
 import pytest
 import keyring
 from jaraco.context import suppress
 
 import wolframalpha
 
 
-if six.PY2:
-    collect_ignore = [
-        'wolframalpha/pmxbot.py',
-        'wolframalpha/test_pmxbot.py',
-    ]
-
-
 @suppress(Exception)
 def from_keyring():
     return keyring.get_password('https://api.wolframalpha.com/', getpass.getuser())