[ember-moment] attempted to set timezone, but moment-timezone is not setup.

I'm getting `[ember-moment] attempted to set timezone, but moment-timezone is not setup.` and I've read through the other issues in this repo and tried everything with no luck.

```
$ ember -v

ember-cli: 2.18.2
node: 10.14.2
```

```
$ bower list

├── moment#2.24.0
├─┬ moment-timezone#0.5.25
│ └── moment#2.24.0
```

```
// environment.js

module.exports = function(environment) {
let ENV = {
// ...
moment: {
includeTimezone: 'all'
}
};
return ENV;
};
```

Nothing related to moment in `ember-cli-build.js`.

Any ideas? Thanks!