onerror now producing warnings in Python 3.12 latest alpha

[henryiii]

Using onerror is producing warnings in the latest Python 3.12 alpha.

I believe it's used here:

wheel/src/wheel/bdist_wheel.py

Line 419 in c87e6ed

rmtree(self.bdist_dir, onerror=remove_readonly)

And deprecated here: python/cpython#102829 & changelog: https://docs.python.org/zh-cn/3.12/whatsnew/3.12.html - to be removed in 3.14.

(It's breaking my tests where I have warnings as errors on)