Pico W: Initial Wi-Fi support (#2980)

* Pico W: Initial WiFi support: connects, but freezes after a while

* Update arduino-pico core to fix hang with Wi-Fi

* Add `picow` to workflow since it's different from `pico` now

variants/rpipicow/variant.h

@@ -4,6 +4,10 @@
 
 #define ARDUINO_ARCH_AVR
 
+#ifndef HAS_WIFI
+#define HAS_WIFI 1
+#endif
+
 #define USE_SH1106 1
 
 // default I2C pins:
@@ -46,4 +50,4 @@
 #define SX126X_RESET LORA_RESET
 #define SX126X_DIO2_AS_RF_SWITCH
 #define SX126X_DIO3_TCXO_VOLTAGE 1.8
-#endif
+#endif