Switch from unmaintained appdirs to the drop-in replacement platformdirs

[CAM-Gerlach]

I couldn't open an issue or search for code use since this is marked as a fork, so I cloned the repo and went straight for a PR; hope that's okay.

In any case, for some background, I'd observed a crash in the PRAW pre-commit suite that I discovered was fixed in #30 while working on the PR we've discussed to simplify and unify the PRAW linting situation, which ironically enough apparently initially went unnoticed due to that very issue (as otherwise the CIs would have immediately flagged the issue), the linting suite on the CIs and in the pre-push script having different versions and config then the pre-commit suite and not running in isolated envs (I'll pre-commit autoupdate to pull in the fixed version).

Anyway, all that aside, given it was just added as a dep I wanted to let you know that appdirs is effectively unmaintained and platformdirs is the community's drop-in replacement.

Black, Pylint and other major projects have already switched, and given this dep was newly added, it would make sense to use the modern, maintained replacement now given its drop-in compatible and fixes numerous long-outstanding bugs with the original, instead of having to switch later when things eventually break. It also slightly simplifies the code, as platformdirs has native support for outputing pathlib.Paths.

[CAM-Gerlach]

Hey @LilSpazJoekp , could you review and approve the workflow run? Thanks!

[LilSpazJoekp]

Looks good to me! Would you like to add yourself to the AUTHORS.rst file?

[CAM-Gerlach]

@LilSpazJoekp Up to you; right now it just lists the original rstformat author and the docstrfmt maintainer, so I'd presumably have to add a new section for contributors and list myself there. My typical preference is to limit the explicit listings in the manual Authors file to just authors and maintainers and include a reference to the GitHub contributors listing for the rest, which automatically tracks the rest from basic Git metadata. This minimizes manual maintenance burden and merge conflicts, avoids exposing user emails in an easier to scrape plain text file and eliminates duplication with what Git already tracks. However, I'm happy to add it if that's what you'd prefer as maintainer, just let me know.

[LilSpazJoekp]

You raise many good points. I'm good with just adding a link to the contributors on GitHub.

[CAM-Gerlach]

Thanks @LilSpazJoekp !