Re-enable sky parameters in the editor

Assets/ScriptableRenderLoop/HDRenderLoop/Editor/HDRenderLoopInspector.cs

             EditorGUI.indentLevel++;
             EditorGUI.BeginChangeCheck();
 
-            /*
-            skyParameters.skyHDRI = (Cubemap)EditorGUILayout.ObjectField("Cubemap", skyParameters.skyHDRI, typeof(Cubemap), false);
+            skyParameters.skyHDRI = (Texture)EditorGUILayout.ObjectField("Cubemap", skyParameters.skyHDRI, typeof(Cubemap), false);
-            */
- 
+
             if (EditorGUI.EndChangeCheck())
             {
                 EditorUtility.SetDirty(renderLoop); // Repaint