Support for latest ember-intl addon version

I want to use ember-intl addon.
```
"dependencies": {
"jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.js",
"ember": "3.18.1",
"ember-template-compiler": "3.18.1",
"ember-testing": "3.18.1"
},
"addons": {
"@glimmer/component": "1.0.0",
"ember-intl": "5.3.0",
"ember-data": "3.18.0"
}
```
Wrote en-us translations file, but I have an error:
`WARNING: [ember-intl] translation: "foo" on locale: "en-us" was not found.`

Thank