Fix respawn part of BananaLogic (#2277)

Fix the bug of "respawn" part that cause all the banana respawn in the first Area.

UnitySDK/Assets/ML-Agents/Examples/BananaCollectors/Scripts/BananaLogic.cs

         if (respawn) 
         {
             transform.position = new Vector3(Random.Range(-myArea.range, myArea.range), 
-                                             transform.position.y + 3f, 
-                                             Random.Range(-myArea.range, myArea.range));
+                                             3f, 
+                                             Random.Range(-myArea.range, myArea.range)) + myArea.transform.position;
         }
         else 
         {