Add v4.0.0-beta.2 to CHANGELOG
Add v4.0.0-beta.2 to CHANGELOG

(cherry picked from commit fa88559c2a256ab8dca513dc02d02ad56ffda497)

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