Add changelog for release 0.8.0
Add changelog for release 0.8.0

fasteragile/ember-pikaday,LevelbossMike/ember-pikaday,helm-inc/ember-pikaday-time,LevelbossMike/ember-pikaday,joshuairl/ember-pikaday-with-time,leizhao4/ember-pikaday,Inkstone-Inc/ember-pikaday-time,helm-inc/ember-pikaday-time,leizhao4/ember-pikaday,GabKlein/ember-pikaday,edgycircle/ember-pikaday,digitallumens/ember-pikaday,jeffreybiles/ember-pikaday,GabKlein/ember-pikaday,joshuairl/ember-pikaday-with-time,Inkstone-Inc/ember-pikaday-time,jeffreybiles/ember-pikaday,edgycircle/ember-pikaday,fasteragile/ember-pikaday,digitallumens/ember-pikaday