Add my email to AUTHORS as well

The pull request has been merged faster than I was able to fix that
mistack. :) Sorry.

AUTHORS

@@ -56,7 +56,7 @@ Phill Luby <[email protected]>
 Piotr Bejda <[email protected]>
 Ryan Sullivan <[email protected]>
 Sergey Mishin <[email protected]>
-Stefan Tatschner <[email protected]>
+Stefan Tatschner <[email protected]> <[email protected]>
 Tim Abell <[email protected]>
 Tobias Nygren <[email protected]>
 Tomas Cerveny <[email protected]>