rafthttp: add 3.3.0 support

Signed-off-by: Gyuho Lee <gyuhox@gmail.com>

rafthttp/stream.go

@@ -55,6 +55,7 @@ var (
 		"3.0.0": {streamTypeMsgAppV2, streamTypeMessage},
 		"3.1.0": {streamTypeMsgAppV2, streamTypeMessage},
 		"3.2.0": {streamTypeMsgAppV2, streamTypeMessage},
+		"3.3.0": {streamTypeMsgAppV2, streamTypeMessage},
 	}
 )