Add v4.0.0-beta.4 to CHANGELOG`
Add v4.0.0-beta.4 to CHANGELOG`

(cherry picked from commit 121155cf0bbfa9eee623a209f712542caea7be8c)

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