change parameters for plus ( Int32 -> Int64) (#2)

* int32 -> int64

* int32 -> int64

Author: nic-chen

proto/helloworld.pb.go

@@ -31,10 +31,10 @@ message HelloReply {
 }
 
 message PlusRequest {
-  int32 a = 1;
-  int32 b = 2;
+  int64 a = 1;
+  int64 b = 2;
 }
 
 message PlusReply {
-  int32 result = 1;
+  int64 result = 1;
 }