Merge branch 'master' of https://github.com/Unity-Technologies/ScriptableRenderLoop into Branch_RemoveBlackSmithSky

ScriptableRenderPipeline/HDRenderPipeline/Material/GGXConvolution/GGXConvolution.cs

 
 namespace UnityEngine.Experimental.Rendering.HDPipeline
 {
+    // For multiple importance sampling
+    // TODO: not working currently, will be updated later
     [GenerateHLSL(PackingRules.Exact)]
     public enum LightSamplingParameters
     {