set up flake8 config compatible to black

Author: RonnyPfannschmidt

tox.ini

@@ -3,7 +3,15 @@ envlist=py{27,34,35,36,37}-test,flake8,check_readme
 
 [flake8]
 max-complexity = 10
-
+max-line-length = 88
+exclude=
+	.git,
+	.tox,
+	.env,
+	.venv,
+	.pytest_cache,
+	__pycache__,
+	./setuptools_scm/win_py31_compat.py
 
 [testenv]
 usedevelop=True