v2.1.0 for ESP32_S2/S3/C3 & LwIP W6100 Ethernet

### Releases v2.1.0

1. Initial coding to port [AsyncUDP](https://github.com/espressif/arduino-esp32/tree/master/libraries/AsyncUDP) to ESP32_S2/S3/C3 boards using `LwIP W6100 Ethernet`
2. Bump up to `v2.1.0` to sync with [AsyncUDP_ESP32_SC_W5500 v2.1.0](https://github.com/khoih-prog/AsyncUDP_ESP32_SC_W5500)

library.json

@@ -2,7 +2,7 @@
   "name":"AsyncUDP_ESP32_SC_W6100",
   "version": "2.1.0",
   "description":"Fully Asynchronous UDP Library for ESP32S2/S3/C3 boards using LwIP W6100 Ethernet. The library is easy to use and includes support for Unicast, Broadcast and Multicast environments",
-  "keywords":"communication, data, async, udp, ntp, time, time-server, server, client, multicast, broadcast, webserver, esp32, esp32-s3, esp32-s2, esp32-c3, W6100, lwip, lwip=w6100, udp-server, udp-multicast-server",
+  "keywords":"communication, data, async, udp, ntp, time, time-server, server, client, multicast, broadcast, webserver, esp32, esp32-s3, esp32-s2, esp32-c3, W6100, lwip, udp-server, udp-multicast-server",
   "authors": 
   [
     {