how to publish vendor from package Laravel 5

So I've my custom Laravel 5.4 package, and i want to publish the vendor packages located into my package, this is my code (PackageServiceProvider.php):

$this->publishes([
  __DIR__.'/../vendor/soundasleep' => public_path('soundasleep'),
], 'html2text');

but when i run php artisan vendor:publish --tag=html2text the vendor is published into public folder and i want to be published into my application vendor, because when i tried use \Html2Text\Html2Text as html2text; into my package routes.php i got class Html2Text\Html2Text not found.

so please if someone has any idea i'll be very appreciative.

via Chebli Mohamed