There's a merged pull request on the void-packages repository

boinc-nox: Add the boinc user to boinc-nox
https://github.com/void-linux/void-packages/pull/38756

Description:
The `boinc` user is created for the boinc package, but not for boinc-nox which breaks it.

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#### Testing the changes
- I tested the changes in this PR: **briefly**