Update dependency ember-qunit to v6

Author: renovate[bot]

package.json

@@ -57,7 +57,7 @@
     "ember-maybe-import-regenerator": "1.0.0",
     "ember-page-title": "7.0.0",
     "ember-power-select": "6.0.1",
-    "ember-qunit": "5.1.5",
+    "ember-qunit": "6.1.1",
     "ember-resolver": "8.0.3",
     "ember-source": "3.28.11",
     "ember-source-channel-url": "3.0.0",