README: Add list of boards with watchdog support

Author: pennam

README.md

@@ -75,6 +75,8 @@ The [1.0.0](https://github.com/arduino-libraries/ArduinoIoTCloud/releases/tag/1.
 ArduinoCloud.begin(ArduinoIoTPreferredConnection, false).
 ```
 
+Whatchdog is enabled by default using the following boards: [`MKR 1000`](https://store.arduino.cc/arduino-mkr1000-wifi), [`MKR WiFi 1010`](https://store.arduino.cc/arduino-mkr-wifi-1010), [`MKR GSM 1400`](https://store.arduino.cc/arduino-mkr-gsm-1400-1415), [`MKR NB 1500`](https://store.arduino.cc/arduino-mkr-nb-1500-1413), [`MKR WAN 1300/1310`](https://store.arduino.cc/mkr-wan-1310), [`Nano 33 IoT`](https://store.arduino.cc/arduino-nano-33-iot), [`Portenta H7`](https://store.arduino.cc/portenta-h7), [`Nano RP2040 Connect`](https://store.arduino.cc/products/arduino-nano-rp2040-connect), [`Nicla Vision`](https://store.arduino.cc/products/nicla-vision), [`OPTA WiFi`](https://store.arduino.cc/products/opta-wifi), [`OPTA RS485`](https://store.arduino.cc/products/opta-rs485), [`OPTA Lite`](https://store.arduino.cc/products/opta-lite), [`GIGA R1 WiFi`](https://store.arduino.cc/products/giga-r1-wifi)
+
 #### Device can not subscribe to `THING_ID`
 ```
 ArduinoIoTCloudTCP::handle_SubscribeMqttTopics could not subscribe to /a/t/xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx/e/i