add the GNU Guix (System) logo to the list of covered distros on archive.s.o

According to @ardumont [1], Guix (or more precisely GNU Guix System) is covered as much as NixOS is by the Software Heritage archive. We have the NixOS logo on archive.s.o, we should have the Guix one too.

[1] swh/meta$901

Migrated from T2880 (view on Phabricator)

Edited Jan 07, 2023 by Phabricator Migration user

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