Update guix recipe

Julien LepillerTue Aug 24 23:21:45+0200 2021

449a176

gitile/assets
namelast commitdate
css/Dark theme and improved markdown styleTue Aug 10 14:45:45+0200 2021
images/License with reuse.software, code is under AGPL, not LGPLSun Mar 21 18:00:42+0100 2021
js/License with reuse.software, code is under AGPL, not LGPLSun Mar 21 18:00:42+0100 2021