Copy a missing field in QuicServerCodecBuilder's copy constructor (#641)

Motivation:
QuicServerCodecBuilder's copy constructor doesn't copy
resetTokenGenerator

Modification:
- Copy resetTokenGenerator when QuicServerCodecBuilder's copy
constructor is used

Result:
QuicServerCodecBuilder's copy constructor copies all fields

codec-classes-quic/src/main/java/io/netty/incubator/codec/quic/QuicServerCodecBuilder.java

@@ -60,6 +60,7 @@ private QuicServerCodecBuilder(QuicServerCodecBuilder builder) {
         streamHandler = builder.streamHandler;
         connectionIdAddressGenerator = builder.connectionIdAddressGenerator;
         tokenHandler = builder.tokenHandler;
+        resetTokenGenerator = builder.resetTokenGenerator;
     }
 
     @Override