Support flake8 v4

[wwuck]

Fixes #36

[mschwager]

Hi there,

Thanks for catching this. It looks like we'll need to drop Python 2.7 support before moving forward with this. Here's the original issue for that: #3. I'll handle that, and updating CI providers, then we can rebase here and get this change in 👍

[mschwager]

Hi again, I removed Python 2.7 support so we should be good to move forward here. I also pulled in the extend_select and extended_default_ignore changes myself to get CI passing. If you'd like to update this PR to just bump requirements.txt, I can pull it in and release a new version of Dlint.

[wwuck]

Thanks for the update. Did you want me to revert the test change?

[mschwager]

Thanks for the update. Did you want me to revert the test change?

Yes, please remove the test since we can't guarantee it'll pass for all supported versions of flake8 (extend_select wasn't added until 4.0.0, and we're claiming 3.6.0 minimum here).

[wwuck]

Done

[mschwager]

Great, thanks again for noticing this!