Add set function to define the response timeout

[CNSNGopenSourceProjects]

I like very much you library, but the 1000ms timeout (on forceUpdate) is too short some time.
I would like to make a suggestion to create a function to allow the definition of the response timeout to be used on forceUpdate().
The default value will be 1000ms, but it can be increased if necessary.

Just for reference, I did the following changes on my implementation for Arduino + ESP32:
On NTPClient.h:

::::::::::::::::::
    unsigned long _responceTimeout = 1000;  // In ms		// <--FC
::::::::::::::::::
    /**
     * Changes the response timeout. Cannot be lower than 1000ms.
     */
	void setTimeResponse(unsigned long timeResponse);	// <- FC
::::::::::::::::::

On NTPClient.cpp:

::::::::::::::::::
bool NTPClient::forceUpdate() {
::::::::::::::::::  // Wait till data is there or timeout...
  // byte timeout = 0;				// <--FC
  unsigned long timeout = 0;		// <--FC
  int cb = 0;
  do {
    delay ( 10 );
    cb = this->_udp->parsePacket();
    //if (timeout > 100) return false; // timeout after 1000 ms		// <--FC
    if (timeout > this->_responceTimeout) return false; // timeout 	// <--FC
    //timeout++;					// <--FC
    timeout+=10;					// <--FC
  } while (cb == 0);

  //this->_lastUpdate = millis() - (10 * (timeout + 1)); // Account for delay in reading the time	// <--FC
  this->_lastUpdate = millis() - timeout + 10; // Account for delay in reading the time			// <--FC
::::::::::::::::::
void NTPClient::setTimeResponse(unsigned long timeResponse) {					// <- FC
  this->_responceTimeout     = (timeResponse <= 1000) ? 1000 : timeResponse;	// <- FC
}									
::::::::::::::::::

Best regards,

Fernando