Update the AUTHORS file, based on git shortlog -s

Fixups:
- Peter Moulder is not a commit author but contributed the UA stylesheet.
- Le-Stagiare is Clément Plasse

AUTHORS

@@ -4,18 +4,29 @@ Authors
 Development Lead:
 
 - Simon Sapin
+- Guillaume Ayoub
 
 Contributors:
 
+- Aarni Koskela
+- Anaèle Baumgartner
 - Andres Riofrio
 - Aymeric Bois
 - Chung Wu
-- Frédérick Deslandes 
-- Guillaume Ayoub
+- Clément Plasse
+- Florian Mounier
+- Frédérick Deslandes
+- Glwadys Fayolle
+- Gregory Brown
+- Joe Hu
 - Johan Dahlin
-- mbarkhau
+- Johannes Duschl
 - Peter Moulder
 - Pierre-Alain Mignot
 - Priit Laes
 - Salem Harrache
 - Sergey Pikhovkin
+- Smylers
+- Thomas Grainger
+- kaikuehne
+- mbarkhau