title: Swagger does not publish assets files in laravel 5.6
body: <p>i have installed laravel 5.6 with Swagger with DarkaOnLine/L5-Swagger package, i have followed the installation instructions that is </p>
  
  <blockquote>
    <p>php composer require "darkaonline/l5-swagger:5.6.*"</p>
    
    <p>php artisan vendor:publish --provider
    "L5Swagger\L5SwaggerServiceProvider"</p>
  </blockquote>
  
  <p>i have also set </p>
  
  <blockquote>
    <p>L5_SWAGGER_GENERATE_ALWAYS=true</p>
  </blockquote>
  
  <p>in my env and created a controller and added</p>
  
  <pre><code>/**
   * @SWG\Swagger(
   *     schemes={"http","https"},
   *     host="api.host.com",
   *     basePath="/",
   *     @SWG\Info(
   *         version="1.0.0",
   *         title="This is my website cool API",
   *         description="Api description...",
   *         termsOfService="",
   *         @SWG\Contact(
   *             email="contact@mysite.com"
   *         ),
   *         @SWG\License(
   *             name="Private License",
   *             url="URL to the license"
   *         )
   *     ),
   *     @SWG\ExternalDocumentation(
   *         description="Find out more about my website",
   *         url="http..."
   *     )
   * )
   */
  </code></pre>
  
  <p>after that i typed </p>
  
  <pre><code>php artisan l5-swagger:generate
  php artisan vendor:publish
  </code></pre>
  
  <p>when i visit /api/documentation i get a white screen and in the console i am getting the following error</p>
  
  <p><a href="https://i.stack.imgur.com/8hTz5.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/8hTz5.png" alt="enter image description here"></a></p>
  
  <p>your help will be highly appreciated.</p>