Update Generator.php

fix php >=7.2 compatibility

Author: opiy-org

src/Generator.php

@@ -158,7 +158,7 @@ protected function getFormRules($action)
         $parameters = $reflector->getParameters();
 
         foreach ($parameters as $parameter) {
-            $class = (string) $parameter->getType();
+            $class = optional($parameter->getType())->getName();
 
             if (is_subclass_of($class, FormRequest::class)) {
                 return (new $class)->rules();
@@ -197,4 +197,4 @@ protected function getActionName($actionName)
 
         return $actionName;
     }
-}
+}