Update flake8 to 3.7.9 (#2345)
Update flake8 to 3.7.9 (#2345)

Update flake8 to 3.7.9
Parbhat/cookiecutter-django-foundation,ryankanno/cookiecutter-django,pydanny/cookiecutter-django,ryankanno/cookiecutter-django,Parbhat/cookiecutter-django-foundation,Parbhat/cookiecutter-django-foundation,ryankanno/cookiecutter-django,pydanny/cookiecutter-django,trungdong/cookiecutter-django,Parbhat/cookiecutter-django-foundation,luzfcb/cookiecutter-django,trungdong/cookiecutter-django,trungdong/cookiecutter-django,pydanny/cookiecutter-django,luzfcb/cookiecutter-django,luzfcb/cookiecutter-django,luzfcb/cookiecutter-django,pydanny/cookiecutter-django,trungdong/cookiecutter-django,ryankanno/cookiecutter-django