Update Misty's GitHub handle

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

Author: thaJeztah

MAINTAINERS

@@ -96,7 +96,7 @@
 	[people.misty]
 	Name = "Misty Stanley-Jones"
 	Email = "misty@docker.com"
-	GitHub = "mstanleyjones"
+	GitHub = "mistyhacks"
 
 	[people.nishanttotla]
 	Name = "Nishant Totla"