Ensure registerLoader method exists on AnnotationReader

`registerLoader` method doesn't exist anymore. We must still check for older versions.

Author: Vincz

src/Config/Parser/AnnotationParser.php

@@ -46,7 +46,7 @@ public static function getAnnotationReader(): Reader
                 throw new ServiceNotFoundException("In order to use annotations, you need to install 'symfony/cache' first. See: 'https://symfony.com/doc/current/components/cache.html'");
             }
 
-            if (class_exists(AnnotationRegistry::class)) {
+            if (class_exists(AnnotationRegistry::class) && method_exists(AnnotationRegistry::class, 'registerLoader')) {
                 AnnotationRegistry::registerLoader('class_exists');
             }
             $cacheKey = md5(__DIR__);