title: Change (e-mail) button colors in Laravel 5.7
body: <p>What is the best way to change the success, error and primary colors in Laravel 5.7?</p>
  
  <p>I have the email.blade.php via <code>php artisan vendor:publish --tag=laravel-notifications</code></p>
  
  <pre><code>...
  {{-- Action Button --}}
  @isset($actionText)
  &lt;?php
      switch ($level) {
          case 'success':
          case 'error':
              $color = $level;
              break;
          default:
              $color = 'primary';
      }
  ?&gt;
  @component('mail::button', ['url' =&gt; $actionUrl, 'color' =&gt; $color])
  ...
  </code></pre>
  
  <p>The template uses the <code>'success'</code>, <code>'error'</code> and <code>'primary'</code> to color the button, but where can I change the values for them?</p>