title: Symfony 5.1 Deprecation RouteCollectionBuilder -> RoutingConfigurator
body: <p>I am updating a Symfony project from 5.0 to 5.1
  There is this one deprecation hint saying <code>RouteCollectionBuilder</code> is deprecated and <code>RoutingConfigurator</code> should be used instead.</p>
  
  <p>The exact message is</p>
  
  <blockquote>
    <p>Since symfony/routing 5.1: The
    "Symfony\Component\Routing\RouteCollectionBuilder" class is
    deprecated, use
    "Symfony\Component\Routing\Loader\Configurator\RoutingConfigurator"
    instead.</p>
  </blockquote>
  
  <p>How is this supposed to be implemented?
  Am I supposed to change code in the vendors folder?</p>