title: Can't exclude ferries, tolls or motorways on the mapbox route
body: <p>I'm using <a href="https://github.com/mapbox/mapbox-gl-directions" rel="nofollow noreferrer">mapbox-gl-directions</a>, version: <code>4.0.2</code>. I want to exclude tolls, ferries or motorways. Here is a documentation: <a href="https://docs.mapbox.com/api/navigation/#retrieve-directions" rel="nofollow noreferrer">API</a> and it says you can pass <code>exclude</code> parameter:<a href="https://i.stack.imgur.com/dib5D.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/dib5D.png" alt="exclude property"></a><br>
  But while passing it like this, it doesn't work:</p>
  
  <pre><code>new MapboxDirections({
        accessToken: this.accessToken,
        unit: 'metric',
        profile: 'mapbox/driving',
        flyTo: false,
        styles,
        controls: {
          inputs: false,
          instructions: false,
          profileSwitcher: false
        },
        exclude: 'ferry'
      });
  </code></pre>
  
  <p>Has anyone any idea how to pass it?</p>