Let the socket to properly close

python was keeping the connection open and sending duplicate FINs until
the ESP came back online, because the ESP was resetting without giving
the network a chance to answer and close

libraries/ArduinoOTA/ArduinoOTA.cpp

@@ -144,6 +144,8 @@ void ArduinoOTAClass::_runUpdate(){
 
   if(Update.end()){
     client.print("OK");
+    client.stop();
+    delay(10);
 #if OTA_DEBUG
     Serial.printf("Update Success\nRebooting...\n");
 #endif