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

https://github.com/pbui/void-packages polybar
https://github.com/void-linux/void-packages/pull/16051

polybar: update to 3.4.1.
Upstream drops Python2 for Python3.

A patch file from https://github.com/void-linux/void-packages/pull/16051.patch is attached