MAINT: updating url for logo after GH org name change

Author: bsipocz

organisations.yml

@@ -18,4 +18,4 @@ radis: 'https://openastronomy.org/img/members/radis_ico.png'
 astronomy-commons: 'https://openastronomy.org/img/members/astronomy-commons.png'
 stingray: 'https://github.com/StingraySoftware.png?size=40'
 gnuastro: 'https://openastronomy.org/img/members/gnuastro.svg'
-irsa-fornax: 'https://github.com/fornax-navo.png?size=40'
+irsa-fornax: 'https://github.com/nasa-fornax.png?size=40'