fix/pin-flake8-pyprojecttoml-to-fix-lint

[evamaxfield]

Lint is broken because flake8-pyprojecttoml released a new version (but its breaking?? not really sure).

Context: because projects are slowly moving over to pyproject.toml files to maintain all their metadata, deps, and tooling stuff, we want to store everything we can in that one file. flake8 the linter doesn't yet support the pyproject.toml file for reading its configurations. the flake8-pyprojecttoml library is a sort of experimental plugin that enables that reading.

I will look for better / more stable ways to handle this in the future.

[evamaxfield]

Seems like this may be a bit more stable: https://github.com/john-hen/Flake8-pyproject

Will check it out later.

[codecov-commenter]

Codecov Report

Base: 90.51% // Head: 90.51% // No change to project coverage :thumbsup:

Coverage data is based on head (82e283d) compared to base (de2b68b). Patch has no changes to coverable lines.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #130 +/- ## ======================================= Coverage 90.51% 90.51% ======================================= Files 97 97 Lines 3510 3510 ======================================= Hits 3177 3177 Misses 333 333 ``` Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None)

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