Use pre-commit

[kurtmckee]

I saw in #290 that not only are there flake8 issues, but that pre-commit was desirable for the project. Great!

This PR introduces a number of pre-commit hooks that format and lint the code. I also manually fixed all of the flake8 issues, as well as an issue found by actionlint.

Note

I am not adding pre-commit to CI; instead, you should enable pre-commit.ci for the repo, which has the following benefits:

• PR branches will be auto-updated with an additional commit by pre-commit.ci if code formatters make changes.
• pre-commit.ci will submit PRs once each quarter to auto-update the hook versions as new versions are released.

For these reasons, running pre-commit in GitHub Actions is not the best practice.

Closes #290

---

@JessicaTegner I'm going to pause contributions for now until I hear back about the existing PRs. Any other work that I might do in parallel would likely have merge conflicts with this PR, for example.

Thanks for reviewing some of my previous PRs already! 🥳

[kurtmckee]

I'm working on addressing the merge conflicts now.

[JessicaTegner]

Hey @kurtmckee

Thank so much for all your prs. Amazing work 🎉

All your other prs has been merged in, so this is the last one (for now) remaining.

After this one, feel free to add another pr with the ci changes if you wish, if not, just let me know :)

Thanks again.
PS: Feel free to add yourself to the list, and just write a quick oneliner with everything you did :)

[kurtmckee]

add another pr with the ci changes

I won't be able to set up pre-commit.ci for the repo. It's a GitHub app that you -- as the repo owner -- have to authorize. I highly recommend doing so!

I added myself to the bottom of the contributors list.

Have a great day!