Add changelog entry about scaling as Torflow by default

CHANGELOG.md

@@ -48,6 +48,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
   ``dependency_links`` is needed until #26914 is fixed. (#27704)
 - documentation cleanup (#27773)
   - split, merge, simplify, extend, reorganize sections and files
+- generate scales as Torflow by default (#27976)
 
 ## [0.7.0] - 2018-08-09