bug#26667: Add: guix-fish 0.1.0

[ng0]

Hi,

it's the little things which sometimes count:

I have just released version 0.1.0 of fish-guix.

This happened in between moving everything relevant to
the page I've decided on for now, so just ignore most
of the content and just look at
https://pragmatique.noblogs.org/software/fish-guix/ or
https://pragmatique.noblogs.org/software/fish-guix/downloads/

The appended patch adds the package to Guix.
-- 
PGP and more: https://people.pragmatique.xyz/ng0/