[bug#66296] [PATCH] pack: Allow setting a custom image tag for Docker images

[Mathieu Othacehe <othacehe@gnu.org>]

Hello,

> Inspired by `docker build -t`, this commit adds a new Docker-specific
> option to `guix pack` which allows setting a custom repository name for
> the resulting image. If this option is not specified, pack falls back
> to computing the name from the manifest. Therefore, this change is
> entirely backwards compatible.

This seems to work fine, thanks. There is a line in the documentation
that states:

--8<---------------cut here---------------start------------->8---
The “repository name” as it appears in the output of the docker images
command is computed from package names passed on the command line or in
the manifest file.
--8<---------------cut here---------------end--------------->8---

Could you build upon that statement and introduce the new --image-tag
field there?

Thanks,

Mathieu