fix: Add autoloader

Signed-off-by: Joas Schilling <coding@schilljs.com>

Author: nickvergessen

composer/autoload.php

@@ -0,0 +1,9 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * SPDX-FileCopyrightText: 2023 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+require_once __DIR__ . '/../vendor/autoload.php';