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

common/container: move masterdir image building to void-packages
https://github.com/void-linux/void-packages/pull/45320

Description:
see void-linux/void-docker#11

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#### Testing the changes
- I tested the changes in this PR: **YES**
- example CI run with the new image: https://github.com/classabbyamp/void-packages/actions/runs/5843401357

before:
```
ghcr.io/void-linux/xbps-src-masterdir   latest-x86_64        607MB
ghcr.io/void-linux/xbps-src-masterdir   latest-x86_64-musl   522MB
```
after:
```
localhost:5000/void-buildroot-glibc    latest   438MB
localhost:5000/void-buildroot-musl     latest   383MB
```