update soccer-2v1 reward function from test branch

Project/Assets/ML-Agents/Examples/Soccer/Scripts/AgentSoccer.cs

     float m_ForwardSpeed;
 
     [HideInInspector]
+    public float timePenalty = 0;
+
+    [HideInInspector]
     public Rigidbody agentRb;
     SoccerSettings m_SoccerSettings;
     BehaviorParameters m_BehaviorParameters;
             // Existential bonus for Goalies.
             AddReward(1f / 3000f);
         }
+        else if (position == Position.Striker)
+        {
+            // Existential penalty for Strikers
+            AddReward(-1f / 3000f);
+        }
-            // Existential penalty for Strikers/Generic.
-            AddReward(-1f / 3000f);
+            // Existential penalty cumulant for Generic
+            timePenalty += -1f / 3000f;
         }
         MoveAgent(vectorAction);
     }
 
     public override void OnEpisodeBegin()
     {
+
+        timePenalty = 0;
         m_BallTouch = SideChannelUtils.GetSideChannel<FloatPropertiesChannel>().GetPropertyWithDefault("ball_touch", 0);
         if (team == Team.Purple)
         {

Project/Assets/ML-Agents/Examples/Soccer/Scripts/SoccerFieldArea.cs

         {
             if (ps.agentScript.team == scoredTeam)
             {
-                ps.agentScript.AddReward(1);
+                ps.agentScript.AddReward(1 + ps.agentScript.timePenalty);
             }
             else
             {