Update announcements.json

announcements.json

 [
     {"id":21,"title":"捐款地址更改为 my-card.in/donate ","url":"http://my-card.in/donate","created_at":"2014-05-06T10:34:06+08:00","updated_at":"2014-05-06T10:34:06+08:00"},
-    {"id":20,"title":"周赛4月奖励开始！","url":"http://www.duelcn.com/forum.php?mod=viewthread&tid=60680&extra=page%3D1","created_at":"2014-04-1T10:34:06+08:00","updaedt_at":"2014-05-1T10:34:06+08:00"},
     {"id":18,"title":"游戏王竞赛联盟~周赛","url":"http://www.duelcn.com/thread-59882-1-1.html","created_at":"2013-12-01T18:55:06+08:00","updated_at":"2030-10-22T10:34:06+08:00"},
     {"id":4,"title":"QQ群: Mycard - 萌卡(225669895)","url":"http://qun.qzone.qq.com/group#!/225669895/home","created_at":"2013-02-19T18:12:07+08:00","updated_at":"2013-02-19T07:12:08+08:00"}
 ]