Revert "Updating CHANGELOG for 0.21.0 release."
Revert "Updating CHANGELOG for 0.21.0 release."

This reverts commit ed8a33b40778e76c7577437545572fe5bf28f611.

medallia/aurora,medallia/aurora,thinker0/aurora,medallia/aurora,apache/aurora,apache/aurora,medallia/aurora,apache/aurora,apache/aurora,rdelval/aurora,medallia/aurora,rdelval/aurora,medallia/aurora,rdelval/aurora,thinker0/aurora,apache/aurora,apache/aurora,thinker0/aurora,thinker0/aurora,rdelval/aurora,rdelval/aurora,thinker0/aurora,rdelval/aurora,thinker0/aurora