goprotobuf: Add weekly.2011-12-06 entry to .hgtags.

R=adg
TBR=adg
CC=golang-dev
http://codereview.appspot.com/5461045

.hgtags

@@ -18,3 +18,4 @@ bc76a153ffde5de8535b7c2791102ddd0b93f187 go.weekly.2011-09-21
 a13c0e6343c49dc738c218ea43cab675865136dc go.weekly.2011-10-26
 694312d6c9bb86513f52e38db02c2d0f84b181ce go.weekly.2011-11-02
 458bd32e66bc173c6c12743d375dfa20b145a31f go.weekly.2011-11-09
+baa3174c862d6d0b5a44044c385736f633e10a85 go.weekly.2011-12-06