t_httpUpdate_return ret = ESPhttpUpdate.update("192.168.0.2", 80, "/esp/update/arduino.php", "optional current version string here");
switch(ret) {
	case HTTP_UPDATE_FAILED:
		Serial.println("[update] Update failed.");
		break;
	case HTTP_UPDATE_NO_UPDATES:
		Serial.println("[update] Update no Update.");
		break;
	case HTTP_UPDATE_OK:
		Serial.println("[update] Update ok."); // may not called we reboot the ESP
		break;
}