Update AUTHORS.txt

Author: robertfoss

AUTHORS.txt

@@ -709,6 +709,7 @@ Rob Hoelz <rob@hoelz.ro>
 Robert Buonpastore <robert.buonpastore@gmail.com>
 Robert Clipsham <robert@octarineparrot.com>
 Robert Gawdzik <rgawdzik@hotmail.com>
+RObert Foss <dev@robertfoss.se>
 Robert Irelan <rirelan@gmail.com>
 Robert Knight <robertknight@gmail.com>
 Robert Millar <robert.millar@cantab.net>