Removed old ScriptableRenderLoop and Pipeline namespaces.

Assets/LowEndRenderLoop/LowEndRenderPipeline.cs

 using UnityEngine;
 using UnityEngine.Experimental.Rendering;
-using UnityEngine.Experimental.ScriptableRenderLoop;
-using UnityEngine.ScriptableRenderPipeline;
 
 #region RenderPipelineInstance
 public class LowEndRenderPipelineInstance : RenderPipeline