fix ember-try scenarios

Author: mansona

.github/workflows/ci.yml

@@ -134,7 +134,6 @@ jobs:
           - ember-release
           - ember-beta
           - ember-canary
-          - ember-classic
           - embroider-safe
           - embroider-optimized
           - no-deprecations

packages/ember-cli-fastboot/tests/dummy/config/ember-try.js

@@ -12,6 +12,7 @@ module.exports = async function () {
         npm: {
           devDependencies: {
             'ember-source': '~3.16.0',
+            'ember-qunit': '^5.0.0',
           },
         },
       },
@@ -20,6 +21,7 @@ module.exports = async function () {
         npm: {
           devDependencies: {
             'ember-source': '~3.20.5',
+            'ember-qunit': '^5.0.0',
           },
         },
       },
@@ -28,6 +30,7 @@ module.exports = async function () {
         npm: {
           devDependencies: {
             'ember-source': '~3.24.3',
+            'ember-qunit': '^5.0.0',
           },
         },
       },