Update rest-versioning.md [skip ci]

Add module controller namespace in config to fix:

```
{
    name: "Not Found",
    message: "Unable to resolve the request "v1/country/index".",
    code: 0,
    status: 404,
    type: "yii\web\NotFoundHttpException",
    previous: {
        name: "Invalid Route",
        message: "Unable to resolve the request "v1/country/index".",
        code: 0,
        type: "yii\base\InvalidRouteException"
    }
}
```