Prepare to release 0.13.0 (#206)

## CHANGELOG

#203
- Update README to use new syntax and Glimmer Components
- Update dummy app to new Ember syntax and Angle Bracket Components

#163
- BREAKING CHANGES: dropped node v6 and ember < 3.8
- Internally we switched from ember-mocha to ember-qunit because ember-mocha is not maintained.

#184
- use Ember.set to set value, works with Glimmer Components

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@microstates/ember",
-  "version": "0.12.3",
+  "version": "0.13.0",
   "description": "Data Down, Actions Up: at the molecular level.",
   "keywords": [
     "ember-addon",