Typo fix

Author: hobinjk

examples/PlatformIO/BME280/src/BME280.cpp

@@ -122,7 +122,7 @@ void setup() {
   digitalWrite(LED_BUILTIN, PIN_STATE_HIGH);
   adapter = new WebThingAdapter("weathersensor", WiFi.localIP());
 
-  weatherTemp.unit = "c";
+  weatherTemp.unit = "celsius";
   weather.addProperty(&weatherTemp);
   weather.addProperty(&weatherPres);
   weather.addProperty(&weatherHum);