goprotobuf: add a .hgtags so people can easily sync

the protobuf code to the stable or weekly go release.

R=rsc, dsymonds
CC=golang-dev
http://codereview.appspot.com/4373053

.hgtags

@@ -0,0 +1,4 @@
+f3ef978cda6fabc10f6039aeed960340547c6d5a release.r56
+f3ef978cda6fabc10f6039aeed960340547c6d5a release
+96dad172ec5b1aa6946f13f9cbf9cfe0fec40f05 weekly.2011-04-04
+96dad172ec5b1aa6946f13f9cbf9cfe0fec40f05 weekly