Fixed obsolete API usage with latest trunk

Author: JulienIgnace-Unity

com.unity.render-pipelines.high-definition/Runtime/Sky/SkyManager.cs

@@ -537,7 +537,7 @@ internal void SetupAmbientProbe(HDCamera hdCamera)
             RenderSettings.ambientIntensity = 1.0f;
             RenderSettings.ambientMode = AmbientMode.Skybox; // Force skybox for our HDRI
             RenderSettings.reflectionIntensity = 1.0f;
-            RenderSettings.customReflection = null;
+            RenderSettings.customReflectionTexture = null;
         }
 
         void BlitCubemap(CommandBuffer cmd, Cubemap source, RenderTexture dest)
@@ -1254,7 +1254,7 @@ void OnBakeStarted()
             RenderSettings.ambientIntensity = 1.0f;
             RenderSettings.ambientMode = AmbientMode.Skybox; // Force skybox for our HDRI
             RenderSettings.reflectionIntensity = 1.0f;
-            RenderSettings.customReflection = null;
+            RenderSettings.customReflectionTexture = null;
 
             DynamicGI.UpdateEnvironment();
         }