fix ember-data-store-extends frontmatter

Author: mansona

content/ember-data/v5/ember-data-deprecate-store-extends-ember-object.md

@@ -1,7 +1,7 @@
 ---
 title: Store will no longer extend EmberObject in 6.0
-until: 6.0
-since: 5.4
+until: '6.0'
+since: '5.4'
 displayId: ember-data:deprecate-store-extends-ember-object
 ---
 
@@ -28,4 +28,4 @@ If you are unsure whether your Store class uses EmberObject APIs, set this
 config and uses of those APIs will throw exceptions. The most common API that 
 may have been used is `Store.extend({...`.
 
-This deprecation is from RFC [#1026](https://rfcs.emberjs.com/id/1026-ember-data-deprecate-store-extends-ember-object).
+This deprecation is from RFC [#1026](https://rfcs.emberjs.com/id/1026-ember-data-deprecate-store-extends-ember-object).