Ember upgrade for addons/core (#2777)

addons/core/tests/dummy/config/ember-cli-update.json

@@ -3,7 +3,7 @@
   "packages": [
     {
       "name": "ember-cli",
-      "version": "4.12.2",
+      "version": "5.12.0",
       "blueprints": [
         {
           "name": "addon",

addons/core/tests/dummy/config/ember-try.js

@@ -12,18 +12,18 @@ module.exports = async function () {
   return {
     scenarios: [
       {
-        name: 'ember-lts-4.4',
+        name: 'ember-lts-4.12',
         npm: {
           devDependencies: {
-            'ember-source': '~4.4.0',
+            'ember-source': '~4.12.0',
           },
         },
       },
       {
-        name: 'ember-lts-4.8',
+        name: 'ember-lts-5.4',
         npm: {
           devDependencies: {
-            'ember-source': '~4.8.0',
+            'ember-source': '~5.4.0',
           },
         },
       },

addons/core/tests/helpers/index.js

@@ -9,7 +9,7 @@ import {
   setupTest as upstreamSetupTest,
 } from 'ember-qunit';
 
-// This file exists to provide wrappers around ember-qunit's / ember-mocha's
+// This file exists to provide wrappers around ember-qunit's
 // test setup functions. This way, you can easily extend the setup that is
 // needed per test type.