There is a new pull request by ahesford against master on the void-packages repository

https://github.com/ahesford/void-packages py3protobuf
https://github.com/void-linux/void-packages/pull/22388

python-protobuf: update to 3.12.2.
@clehner: Are you still interested in maintaining this?

A patch file from https://github.com/void-linux/void-packages/pull/22388.patch is attached