message: follow_me: fly lower, and behind
  Flying lower and especially behind makes it more obvious what is
  happening.
diff: @@ -108,8 +108,8 @@ int main(int argc, char **argv)
  // Configure Min height of the drone to be "20 meters" above home & Follow direction as "Front
  // right".
  FollowMe::Config config;
  - config.min_height_m = 20.0;
  - config.follow_direction = FollowMe::Config::FollowDirection::FRONT_RIGHT;
  + config.min_height_m = 10.0;
  + config.follow_direction = FollowMe::Config::FollowDirection::BEHIND;
  FollowMe::Result follow_me_result = follow_me->set_config(config);
  // Start Follow Me
  