Update flake8 to 3.9.1#177

pyup-bot wants to merge 1 commit intomasterdovpanda-dev/dovpanda:masterfrom

pyup-update-flake8-3.7.9-to-3.9.1dovpanda-dev/dovpanda:pyup-update-flake8-3.7.9-to-3.9.1Copy head branch name to clipboard