Apply rector, phpstan and php-cs-fixer

rector.php

@@ -0,0 +1,33 @@
+<?php
+
+declare(strict_types=1);
+
+use Rector\CodeQuality\Rector\Class_\InlineConstructorDefaultToPropertyRector;
+use Rector\Config\RectorConfig;
+use Rector\Set\ValueObject\LevelSetList;
+use Rector\Set\ValueObject\SetList;
+
+return static function (RectorConfig $rectorConfig): void {
+    $rectorConfig->paths(
+        [
+            __DIR__.'/src',
+            __DIR__.'/tests',
+        ]
+    );
+
+    // register a single rule
+    $rectorConfig->rule(InlineConstructorDefaultToPropertyRector::class);
+
+    // define sets of rules
+    $rectorConfig->sets(
+        [
+            LevelSetList::UP_TO_PHP_81,
+            SetList::CODE_QUALITY,
+            SetList::CODING_STYLE,
+            SetList::TYPE_DECLARATION_STRICT,
+            SetList::NAMING,
+            SetList::PRIVATIZATION,
+            SetList::EARLY_RETURN,
+        ]
+    );
+};