bug#61513: emacs-next@29.0.60 self-reports as version 30.0.50

[Jelle Licht]

Hi guix,

Since commit 6f0c905324 on master, the version of our emacs-next package
was bumped to 29.0.60(-0.ac7ec87).

Yet:
--8<---------------cut here---------------start------------->8---
jlicht@revint ~$ guix shell --pure emacs-next -- emacs --version
GNU Emacs 30.0.50
--8<---------------cut here---------------end--------------->8---

Is this some peculiarity of the Emacs's development cycle, or did we end
up having a "emacs-next-next" package?

Kind regards,
- Jelle