Fix EventDispatcer & events

Looks like parameter for the `->dispatch(` have been flipped (event first then event name).
Define events should now extends `Symfony\Contracts\EventDispatcher\Event`

tests/Wallabag/CoreBundle/Event/Listener/LocaleListenerTest.php

@@ -69,8 +69,8 @@ class LocaleListenerTest extends TestCase
         $dispatcher->addSubscriber($listener);
 
         $dispatcher->dispatch(
-            KernelEvents::REQUEST,
-            $event
+            $event,
+            KernelEvents::REQUEST
         );
 
         $this->assertSame('fr', $request->getLocale());