Upgrade PyO3 (0.23.x -> 0.27.x)

[Qqwy]

Opsqueue's Python library uses PyO3 to generate FFI bindings.

The PyO3 project is evolving fast, with a lot of fixes and improvements happening in the past year.
However, there are some changes to the API / Rust macros, which means that some of the PyO3 annotations will need to be rewritten to be compatible with the newer version.

An important reason to perform this upgrade soon, is so we can support Python 3.14.x

Steps:

• Blindly try to upgrade and see how much things break
• Open up one or more follow-up issues depending on how much work this turns out to be.