Add support for Python 3.11 and PyPy3.9

[hugovk]

Changes proposed in this pull request:

• Support Python 3.11:
  • add Trove classifier
  • test on CI
  • build wheel
• Create wheel for PyPy3.9

Python 3.11 is currently at release candidate 2, the last one before full release on 2022-10-24, and includes this call to action:

Community members
We strongly encourage maintainers of third-party Python projects to prepare their projects for 3.11 compatibilities during this phase. As always, report any issues to the Python bug tracker 1.

And:

There will be no ABI changes from this point forward in the 3.11 series and the goal is that there will be as few code changes as possible.

So it is pretty safe to release a 3.11 release now. We can label it as a dev preview, and put also out a new release when 3.11.0 is out.

But also, if you'd prefer to wait until the full 3.11.0 release, that's fine too, we've not yet had anyone asking for 3.11 wheels yet.

---

Also in this PR:

• Bump GitHub Actions versions
• GHA: Use ubuntu-latest, except pin to latest 22.04 for the benchmarking

[codecov-commenter]

Codecov Report

Merging #564 (b5ce312) into main (203f311) will increase coverage by 0.00%.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #564   +/-   ##
=======================================
  Coverage   91.58%   91.58%           
=======================================
  Files           6        6           
  Lines        1901     1902    +1     
=======================================
+ Hits         1741     1742    +1     
  Misses        160      160           

Impacted Files	Coverage Δ
tests/test_ujson.py	99.45% <0.00%> (+<0.01%)	⬆️

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[bwoodsend]

RC2 is close enough to the real thing for me. Bombs away...

[JustAnotherArchivist]

Normal release without a dev preview mark or similar sounds good to me.
Other changes look fine as well, thanks!

[JustAnotherArchivist]

I'm getting a red X for the CI on b5ce312 for whatever reason even though all checks passed. Just GitHub Actions being weird?

[bwoodsend]

A red X which, if you click on it, creates a popup showing that all 36 checks passed. 🙄 Is it just me or is GH's web UI getting buggier and buggier...

[hugovk]

I think the red X is because I added the "changelog" label after creating the PR:

So the "Require PR label" action failed, as expected. Then I added it, and it re-ran, and passed, as expected:

But it makes no sense to still show the red X if it later passed... 🤷

[hugovk]

OK, all good to release with these release notes?

https://github.com/ultrajson/ultrajson/releases

[bwoodsend]

Yay! I did something in this one 😄