Fix incorrect port range check

Motivation:

In the Internet Protocol, the valid port number range is from 1 to 65535
(inclusive on the both side.)  However, SocksCmdRequest refuses to
construct itself when the port number 65535 is specified.

Modification:

Do not raise an exception when the specified port number is 65535.

Result:

Fixes #2428

codec-socks/src/main/java/io/netty/handler/codec/socks/SocksCmdRequest.java

@@ -63,7 +63,7 @@ public final class SocksCmdRequest extends SocksRequest {
             case UNKNOWN:
                 break;
         }
-        if (port < 0 && port >= 65535) {
+        if (port < 0 && port >= 65536) {
             throw new IllegalArgumentException(port + " is not in bounds 0 < x < 65536");
         }
         this.cmdType = cmdType;