- Reset sky manager hash when changing parameters.

- Properties info in SkyParameters are now protected in order to be able to override the hash method properly.

Assets/ScriptableRenderLoop/HDRenderLoop/Sky/SkyManager.cs

                 {
                     if (value == null || IsSkyParameterValid(value))
                     {
+                        m_SkyParametersHash = 0;
                         m_SkyParameters = value;
                     }
                     else

Assets/ScriptableRenderLoop/HDRenderLoop/Sky/SkyParameters.cs

         public float multiplier = 1.0f;
         public SkyResolution resolution = SkyResolution.SkyResolution256;
 
-        private FieldInfo[] m_Properties;
+        protected FieldInfo[] m_Properties;
 
         protected void OnEnable()
         {