PyO3 0.23.2

This release fixes a build failure when attempting to compile for free-threaded Python when the abi3 or abi3-pyxx features are enabled. With this fix, the compile will now ignore (with a warning) the abi3 and abi3-pyxx flags (as is the case when compiling for PyPy, as neither support abi3).

This release also iterates upon the new IntoPyObject trait by adding an IntoPyObjectExt helper trait with some common convenience functions.

Finally, a compile failure related to ambiguous_associated_items lint errors inside generated #[pyclass] and #[derive(IntoPyObject)] output has been fixed.

Thank you to the following contributors for the improvements:

@davidhewitt
@LilyFoote
@ngoldbaum