Fix proxy example in README.md

Author: vjik

README.md

@@ -46,6 +46,8 @@ $proxy = $factory->createProxy(
     function (& $wrappedObject, $proxy, $method, $parameters, & $initializer) {
         $wrappedObject = new \MyApp\HeavyComplexObject(); // instantiation logic here
         $initializer   = null; // turning off further lazy initialization
+
+        return true; // report success
     }
 );