Use py36 for black

Author: chdemko

tox.ini

@@ -4,7 +4,8 @@ envlist = py2,py3,py36
 [testenv]
 deps =
 	py2: coverage
-	py3: coverage, pylint
+	py3: coverage
+	py3: pylint
 	py36: black
 commands =
     py2: python2 -W ignore -m coverage run    --source=pandoc_codeblock_include setup.py test