Add myself to the authors file (#3800)

Just adding myself to the authors file for #3787.
Oops: should have done it as part of that MR rather than a separate one.

docs/AUTHORS.txt

@@ -7,6 +7,7 @@ Aaron Ross <aaron@wawd.com>
 Adam Endicott
 Adriano Petrich <petrich@gmail.com>
 Akira Matsuzaki <akira.matsuzaki.1977@gmail.com>
+Alan Brogan <github@al-got-rhythm.net>
 Alec Clowes <aclowes@gmail.com>
 Ales Zoulek <ales.zoulek@gmail.com>
 Allan Caffee <allan.caffee@gmail.com>