Rename setAirspeed into setAirSpeed

mavsdk_wrapper.cpp

@@ -328,7 +328,7 @@ int loiter(double la, double lo, float a, float radius) {
     return result;
 }
 
-int setAirspeed(float airspeed) {
+int setAirSpeed(float airspeed) {
     if (!mavsdk_started)
         return -1;