CI: Fix flake8 logic
When using --select in flake8, the defaults get disabled and effectively flake8 is not checking much errors at all. Revert to using --ignore only.
Also fix some fall-out from this oversight.
When using --select in flake8, the defaults get disabled and effectively flake8 is not checking much errors at all. Revert to using --ignore only.
Also fix some fall-out from this oversight.