chore: tuic server can handle V4 and V5 in same port

transport/tuic/v4/protocol.go

@@ -36,6 +36,8 @@ const (
 	ResponseType     = CommandType(0xff)
 )
 
+const VER byte = 0x04
+
 func (c CommandType) String() string {
 	switch c {
 	case AuthenticateType:
@@ -66,7 +68,7 @@ type CommandHead struct {
 
 func NewCommandHead(TYPE CommandType) CommandHead {
 	return CommandHead{
-		VER:  0x04,
+		VER:  VER,
 		TYPE: TYPE,
 	}
 }