Upgrade Ember.js tracking plan

This is tracking issue to get project up to date from maintenance side.

- [x] Upgrade Ember.js to v3.28 -> https://github.com/minutebase/ember-inline-svg/pull/112
- [ ] Upgrade other dependencies ⌛ 
  - https://github.com/minutebase/ember-inline-svg/pull/114
  - https://github.com/minutebase/ember-inline-svg/pull/115
- [ ] Write change log + release v2.x major