Update pyflakes to 2.3.0#19

pyup-bot wants to merge 1 commit intomasterSuperFeliz/libpythonpro:masterfrom

pyup-update-pyflakes-2.1.1-to-2.3.0SuperFeliz/libpythonpro:pyup-update-pyflakes-2.1.1-to-2.3.0Copy head branch name to clipboard