serializers/dependency: Change "version_id" property key to "version"

This will finally get the "version" relationship in the "dependency" model going

Author: Turbo87

app/serializers/dependency.js

@@ -0,0 +1,7 @@
+import DS from 'ember-data';
+
+export default DS.RESTSerializer.extend({
+    attrs: {
+        version: 'version_id',
+    },
+});