Upgrade to Laravel 9 (#4413)

Co-authored-by: DaneEveritt <dane@daneeveritt.com>

tests/Traits/MocksUuids.php

@@ -1,11 +1,4 @@
 <?php
-/**
- * Pterodactyl - Panel
- * Copyright (c) 2015 - 2017 Dane Everitt <dane@daneeveritt.com>.
- *
- * This software is licensed under the terms of the MIT license.
- * https://opensource.org/licenses/MIT
- */
 
 namespace Pterodactyl\Tests\Traits;
 
@@ -17,15 +10,13 @@ trait MocksUuids
 {
     /**
      * The known UUID string.
-     *
-     * @var string
      */
-    protected $knownUuid = 'ffb5c3a6-ab17-43ab-97f0-8ff37ccd7f5f';
+    protected string $knownUuid = 'ffb5c3a6-ab17-43ab-97f0-8ff37ccd7f5f';
 
     /**
      * Setup a factory mock to produce the same UUID whenever called.
      */
-    public function setKnownUuidFactory()
+    public function setKnownUuidFactory(): void
     {
         $uuid = Uuid::fromString($this->getKnownUuid());
         $factoryMock = m::mock(UuidFactory::class . '[uuid4]', [