v2.1.0 for ESP32 & LwIP Ethernet

### Releases v2.1.0

1. Initial coding to port [AsyncUDP](https://github.com/espressif/arduino-esp32/tree/master/libraries/AsyncUDP) to ESP32 boards using `LwIP W5500, W6100 or ENC28J60 Ethernet`
2. Bump up to v2.1.0 to sync with [AsyncUDP_ESP32_SC_Ethernet v2.1.0](https://github.com/khoih-prog/AsyncUDP_ESP32_SC_Ethernet)

Author: khoih-prog

.codespellrc

@@ -0,0 +1,7 @@
+# See: https://github.com/codespell-project/codespell#using-a-config-file
+[codespell]
+# In the event of a false positive, add the problematic word, in all lowercase, to a comma-separated list here:
+ignore-words-list = ,
+check-filenames =
+check-hidden =
+skip = ./.git,./src,./examples,./Packages_Patches,./LibraryPatches