Add contact shadows for punctual lights

com.unity.render-pipelines.high-definition/CHANGELOG.md

 
 ### Added
 - Add option supportDitheringCrossFade on HDRP Asset to allow to remove shader variant during player build if needed
+- Add contact shadows for punctual lights (in additional shadow settings), only one light is allowed to cast contact shadows at the same time and so at each frame a dominant light is choosed among all light with contact shadows enabled.
 
 ### Changed
 - Re-enable shadow mask mode in debug view