Add v4.0.0-beta.7 to CHANGELOG
Add v4.0.0-beta.7 to CHANGELOG

(cherry picked from commit 5c32ca9cc521c5ece0e80dc109bb9af9fb83ba50)

emberjs/ember.js,sly7-7/ember.js,mixonic/ember.js,tildeio/ember.js,emberjs/ember.js,sly7-7/ember.js,tildeio/ember.js,emberjs/ember.js,tildeio/ember.js,mixonic/ember.js,sly7-7/ember.js,mixonic/ember.js