updated custom modules version flag, installed drupal/core-dev and rector

rector.php

@@ -0,0 +1,16 @@
+<?php
+
+declare(strict_types=1);
+
+use Rector\Config\RectorConfig;
+
+return RectorConfig::configure()
+    ->withPaths([
+        __DIR__ . '/drush',
+        __DIR__ . '/node_modules',
+        __DIR__ . '/scripts',
+        __DIR__ . '/web',
+    ])
+    // uncomment to reach your current PHP version
+    // ->withPhpSets()
+    ->withTypeCoverageLevel(0);