update changlog.md

ScriptableRenderPipeline/HDRenderPipeline/CHANGELOG.md

 - Fix alpha blending of volumetric lighting with transparent objects.
 - Fix the near plane of the V-Buffer causing out-of-bounds look-ups in the clustered data structure.
 - Depth and color pyramid are properly computed and sampled when the camera renders inside a viewport of a RTHandle.
+- Fix decal atlas debug view to work correctly when shadow atlas view is also enabled
 
 ## [2018.1.0b13]