Update dependency ember-qunit to v6

Author: renovate[bot]

package.json

@@ -57,7 +57,7 @@
     "ember-focus-trap": "1.0.1",
     "ember-load-initializers": "2.1.2",
     "ember-page-title": "7.0.0",
-    "ember-qunit": "5.1.5",
+    "ember-qunit": "6.0.0",
     "ember-resolver": "8.0.3",
     "ember-source": "4.7.0",
     "ember-source-channel-url": "3.0.0",