reduce max step

Project/Assets/ML-Agents/Examples/Tennis/Prefabs/TennisArea.prefab

     VectorActionSize: 03000000
     VectorActionDescriptions: []
     VectorActionSpaceType: 1
-  m_Model: {fileID: 11400000, guid: efc1607ab4c1542689d1451983e7dc63, type: 3}
+  m_Model: {fileID: 11400000, guid: 863ea0aaf12aa42a384771c7f79b4bd1, type: 3}
   m_InferenceDevice: 0
   m_BehaviorType: 0
   m_BehaviorName: Tennis
   agentParameters:
     maxStep: 0
   hasUpgradedFromAgentParameters: 1
-  MaxStep: 3000
+  MaxStep: 600
   ball: {fileID: 1273406647218856}
   invertX: 0
   score: 0
     VectorActionSize: 03000000
     VectorActionDescriptions: []
     VectorActionSpaceType: 1
-  m_Model: {fileID: 11400000, guid: efc1607ab4c1542689d1451983e7dc63, type: 3}
+  m_Model: {fileID: 11400000, guid: 863ea0aaf12aa42a384771c7f79b4bd1, type: 3}
   m_InferenceDevice: 0
   m_BehaviorType: 0
   m_BehaviorName: Tennis

Project/Assets/ML-Agents/Examples/Tennis/Scripts/TennisArea.cs

     {
         m_BallRb.AddForce(m_Down);
         var rgV = m_BallRb.velocity;
-        m_BallRb.velocity = new Vector3(Mathf.Clamp(rgV.x, -50f, 50f), Mathf.Min(rgV.y, 35f), rgV.z);
+        m_BallRb.velocity = new Vector3(Mathf.Clamp(rgV.x, -40f, 40f), Mathf.Min(rgV.y, 35f), rgV.z);
     }
 }