There is an updated pull request by sgn against master on the void-packages repository

https://github.com/sgn/void-packages pyqt5-modernize-update-to-5.15.1
https://github.com/void-linux/void-packages/pull/25128

Calibre 5.0.0, python3-PyQt5 build with sip-build
- modernized since it's required for calibre

A patch file from https://github.com/void-linux/void-packages/pull/25128.patch is attached