Adjust flake8 configuration
Adjust flake8 configuration

Default flake8 configuration collides with results black produces.
Adjust line length settings for flake8 checks to respect black format.

christophmeissner/volunteer_planner,coders4help/volunteer_planner,christophmeissner/volunteer_planner,volunteer-planner/volunteer_planner,christophmeissner/volunteer_planner,pitpalme/volunteer_planner,coders4help/volunteer_planner,christophmeissner/volunteer_planner,coders4help/volunteer_planner,volunteer-planner/volunteer_planner,pitpalme/volunteer_planner,coders4help/volunteer_planner,pitpalme/volunteer_planner,volunteer-planner/volunteer_planner,pitpalme/volunteer_planner,volunteer-planner/volunteer_planner