component args error

components.my-component.js

import Component from '@glimmer/component';

export default class MyComponent extends Component {
}

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle'
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<MyComponent @appName={{appName}}/>
<br>
{{outlet}}
<br>
<br>

templates.components.my-component.hbs

<h4>my-component called as using angle bracket syntax</h4>

<div>
<h4>Displaying passed in arg appName as this.appName</h4>
{{this.appName}}
</div>

<div>
<h4>Displaying passed in arg appName as @appName</h4>
{{@appName}}
</div>

twiddle.json

{
  "version": "0.15.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "https://s3.amazonaws.com/builds.emberjs.com/canary/shas/ee8dfa271e8fbfbd085aed615106033be05fb882.tgz",
    "ember-template-compiler": "3.4.3",
    "ember-testing": "3.4.3"
  },
  "addons": {
    "ember-data": "emberjs/data#master"
  }
}