Fix code style

Author: smortexa

src/CreateApplication.php

@@ -9,7 +9,7 @@
 
 class CreateApplication
 {
-    public static Application|null $app = null;
+    public static ?Application $app = null;
 
     public static function app()
     {

tests/Feature/RuleLoaderTest.php

@@ -5,6 +5,7 @@
 use Illuminate\Support\Facades\Artisan;
 use Illuminate\Support\Facades\File;
 use Mortexa\LaravelArkitect\RuleLoader;
+
 use function PHPUnit\Framework\assertEqualsCanonicalizing;
 
 it('loads user\'s rules', function (): void {