added uno r4 into the example

Author: gbr1

examples/micro-ros_publisher_wifi/micro-ros_publisher_wifi.ino

@@ -8,8 +8,8 @@
 
 #include <std_msgs/msg/int32.h>
 
-#if !defined(ESP32) && !defined(TARGET_PORTENTA_H7_M7) && !defined(ARDUINO_GIGA) && !defined(ARDUINO_NANO_RP2040_CONNECT) && !defined(ARDUINO_WIO_TERMINAL)
-#error This example is only available for Arduino Portenta, Arduino Giga R1, Arduino Nano RP2040 Connect, ESP32 Dev module and Wio Terminal
+#if !defined(ESP32) && !defined(TARGET_PORTENTA_H7_M7) && !defined(ARDUINO_GIGA) && !defined(ARDUINO_NANO_RP2040_CONNECT) && !defined(ARDUINO_WIO_TERMINAL) && !defined(ARDUINO_UNOR4_WIFI)
+#error This example is only available for Arduino Portenta, Arduino Giga R1, Arduino Nano RP2040 Connect, ESP32 Dev module, Wio Terminal and Arduino Uno R4 WiFi
 #endif
 
 rcl_publisher_t publisher;