added ARDUINO_ARCH_RP2040 test

stempayload/Payload_BME280_MPU6050_XS/Payload_BME280_MPU6050_XS.ino

@@ -49,6 +49,10 @@ void setup() {
  
   Serial.println("Starting!");
 
+#ifndef ARDUINO_ARCH_RP2040
+  Serial.println("This code is for the Raspberry Pi Pico hardware.");
+#endif	
+ 
   blink_setup();
  
   blink(500);