Update flake8 dependency

Author: Alexander Grant

setup.py

@@ -43,9 +43,9 @@ def get_version(version_tuple):
     'tests_require': ['pytest', 'responses', 'mock']
 }
 
-# Remove flake requirement for versions less than python3
-# if sys.version_info[0] != 3:
-#     extra_opts['setup_requires'].append('flake8')
+# Modify the flake8 requirement
+if sys.version_info[0] != 3:
+    extra_opts['setup_requires'].append('flake8<=2.6.2')
 
 setup(
     name='twitter-ads',