Bump flake8 to 3.4.1

Author: Todd Palino

setup.py

@@ -144,7 +144,7 @@ def run(self):
     ],
     setup_requires=[
         'nose>=1.3.4',
-        'flake8==3.3.0',
+        'flake8==3.4.1',
     ],
     test_suite="nose.collector",
     extras_require={