0.18 release

[davidhewitt]

I think it would be good to cut a new release soon.

What I'd like to see happen before we release:

• Polish the signature work a little more - particularly Automatically generate __text_signature__ for all functions #2784. (Further non-breaking improvements can be added after 0.18.)
• Decide on deprecate required argument after Option<T> without signature #2703.
• I'm tempted to gate the APIs of pyo3::inspect behind an "experimental" feature, because we didn't finish off the rest of the type-hints use case and I'm a bit uneasy on whether it's in the right final shape until we do have the full type-hints pipeline working.
• Add GILOnceCell::get_or_try_init #2398
• fix PyUnicodeDecodeError_Create #2772
• Stop leaking in new_closure #2690
• Decide on Further relax extract_sequence for the upcoming release 0.18 #2632
• Tidy up / merge / close some of the many open PRs.

All other suggestions on what to add to the release are welcome.

[adamreichold]

I think we should finish up #2772 for the release, at least with a plan on how to improve the testing situation for PyPy.

#2690 also looks like something that would be good to finish up before the release.

And finally as it is breaking, I would be glad if we could make a decision on #2632. I don't think we will get further outside input soon and dragging this along further does not seem useful either. So I would suggest we either merge it or close it before the release.

[adamreichold]

#2398 also looks like it would round out our public API nicely but it seems blocked on the author adding tests and expanding the documentation for quite a while. Maybe we should adopt the PR and carry it over the finish line?

[davidhewitt]

Sorry for the slow reply & agreed on all of the above. I have been busy / exhausted so my hope now is that I can put some effort into the release over the Christmas break :)

#2817 which is an issue running embedded PyO3 on 3.11.1 may also need a resolution before the release.