Update CHANGELOG.md

ScriptableRenderPipeline/HDRenderPipeline/CHANGELOG.md

 
 ### Changed, Removals and deprecations
 - Remove Resource folder of PreIntegratedFGD and add the resource to RenderPipeline Asset
+- Default number of planar reflection change from 4 to 2
 
 ### Bug fixes
 - Fix ConvertPhysicalLightIntensityToLightIntensity() function used when creating light from script to match HDLightEditor behavior