message: examples: changes after new connection interface
diff: @@ -524,17 +524,17 @@ int main(int argc, char** argv)
  {
  std::promise<void> prom;
  std::future<void> fut = prom.get_future();
  - mavsdk.register_on_discover([&prom](uint64_t /* uuid*/) { prom.set_value(); });
  + mavsdk.subscribe_on_new_system([&prom]() { prom.set_value(); });
  if (fut.wait_for(std::chrono::seconds(2)) != std::future_status::ready) {
  std::cout << "FAIL\n";
  std::cout << "-> no device found" << std::endl;
  return 1;
  }
  - mavsdk.register_on_discover(nullptr);
  + mavsdk.subscribe_on_new_system(nullptr);
  }
  - System& system = mavsdk.system();
  + auto system = mavsdk.systems().at(0);
  MavlinkPassthrough mavlink_passthrough(system);
  AttitudeData attitude_data{};
  