Update minimum version of ember-qunit.

Author: Robert Jackson

package.json

@@ -34,7 +34,7 @@
     "ember-cli-babel": "^6.0.0-beta.7",
     "ember-cli-test-loader": "^2.0.0",
     "ember-cli-version-checker": "^1.1.4",
-    "ember-qunit": "^2.0.0-beta.1",
+    "ember-qunit": "^2.1.3",
     "qunit-notifications": "^0.1.1",
     "qunitjs": "^2.0.1",
     "resolve": "^1.1.6",