chore(php) #57 : bump PHP version to 8.4

rector.php

@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+use Rector\Config\RectorConfig;
+use Rector\Set\ValueObject\LevelSetList;
+
+return static function (RectorConfig $rectorConfig): void {
+    $rectorConfig->paths([__DIR__ . '/src']);
+
+    // Upgrade to PHP 8.4 syntax
+    $rectorConfig->sets([
+        LevelSetList::UP_TO_PHP_84,
+    ]);
+};