remove Symfony 4.3 event dispatcher deprecation messages

Author: jkabat

src/DynamicRouter.php

@@ -16,6 +16,7 @@
 use Symfony\Cmf\Component\Routing\Event\RouterGenerateEvent;
 use Symfony\Cmf\Component\Routing\Event\RouterMatchEvent;
 use Symfony\Component\EventDispatcher\EventDispatcherInterface;
+use Symfony\Component\EventDispatcher\LegacyEventDispatcherProxy;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\Routing\Exception\MethodNotAllowedException;
 use Symfony\Component\Routing\Exception\ResourceNotFoundException;
@@ -107,6 +108,10 @@ public function __construct(RequestContext $context,
         $this->uriFilterRegexp = $uriFilterRegexp;
         $this->provider = $provider;
 
+        if (class_exists(LegacyEventDispatcherProxy::class)) {
+            $this->eventDispatcher = LegacyEventDispatcherProxy::decorate($eventDispatcher);
+        }
+
         $this->generator->setContext($context);
     }