Update support link

git-svn-id: https://plugins.svn.wordpress.org/username-changer/trunk@983519 b8457f37-d9ea-0310-8a92-e5e31aec5664
Fix contributor

git-svn-id: https://plugins.svn.wordpress.org/username-changer/trunk@983522 b8457f37-d9ea-0310-8a92-e5e31aec5664