Modify crawler to make variable speed use goals

Project/Assets/ML-Agents/Examples/Crawler/Prefabs/CrawlerBase.prefab

   m_Script: {fileID: 11500000, guid: fd48a95d788a348b0b7a8cefd39e7c27, type: 3}
   m_Name: 
   m_EditorClassIdentifier: 
-  observationSize: 3
+  observationSize: 6
 --- !u!1 &4845971001730692034
 GameObject:
   m_ObjectHideFlags: 0

Project/Assets/ML-Agents/Examples/Crawler/Scripts/CrawlerAgent.cs

     /// </summary>
     public override void CollectObservations(VectorSensor sensor)
     {
+        goalSensor = this.GetComponent<GoalSensorComponent>();
         var cubeForward = m_OrientationCube.transform.forward;
 
         //velocity we want to match
         //avg body vel relative to cube
         sensor.AddObservation(m_OrientationCube.transform.InverseTransformDirection(avgVel));
         //vel goal relative to cube
-        sensor.AddObservation(m_OrientationCube.transform.InverseTransformDirection(velGoal));
+        goalSensor.AddGoal(m_OrientationCube.transform.InverseTransformDirection(velGoal));
-        goalSensor = this.GetComponent<GoalSensorComponent>();
         goalSensor.AddGoal(m_OrientationCube.transform.InverseTransformPoint(m_Target.transform.position));
 
         RaycastHit hit;