Simplified updater that reads package lists from /usr/share/moonarch/
instead of syncing a git repo. Designed to be shipped by the
moonarch-git package as /usr/bin/moonarch-update.
Remove chown from archinstall custom-commands so the repo stays
root:root. Use sudo for git operations in update.sh. Any user with
sudo can now run moonarch-update without owning the repo.
