Added Ben Firshman to AUTHORS

AUTHORS

@@ -3,3 +3,4 @@ Grégoire Cachet <gregoire@audacy.fr>
 Vitaly Babiy <vbabiy86@gmail.com>
 Brian Rosner <brosner@gmail.com>
 Sean Creeley <sean.creeley@gmail.com>
+Ben Firshman <ben@firshman.co.uk>