apps/app_dictate: Fix typo in attribution

Last time I checked, it's "Sangoma", not "Samgoma". Thanks to Brian
(GameGamer43) for pointing that out.

Change-Id: I43d7b196f6d7a2b2517b84915e3a8dfbc2894106

apps/app_dictate.c

@@ -5,7 +5,7 @@
  *
  * Anthony Minessale II <anthmct@yahoo.com>
  *
- * Donated by Sangoma Technologies <http://www.samgoma.com>
+ * Donated by Sangoma Technologies <http://www.sangoma.com>
  *
  * See http://www.asterisk.org for more information about
  * the Asterisk project. Please do not directly contact