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

https://github.com/DBLouis/void-packages master
https://github.com/void-linux/void-packages/pull/15421

New package: nextcloudclient-2.6.0.
I am not sure about the dependencies, especially libgnome-keyring.

A patch file from https://github.com/void-linux/void-packages/pull/15421.patch is attached