Fix various compatibility issues with PHP 8

libs/ical/Property/Event/Attachment.php

@@ -0,0 +1,39 @@
+<?php
+
+/*
+ * This file is part of the eluceo/iCal package.
+ *
+ * (c) Markus Poerschke <markus@eluceo.de>
+ *
+ * This source file is subject to the MIT license that is bundled
+ * with this source code in the file LICENSE.
+ */
+
+namespace Eluceo\iCal\Property\Event;
+
+use Eluceo\iCal\Property;
+
+/**
+ * Class Attachment.
+ */
+class Attachment extends Property
+{
+    /**
+     * @param string $value
+     * @param array  $params
+     */
+    public function __construct($value, $params = [])
+    {
+        parent::__construct('ATTACH', $value, $params);
+    }
+
+    /**
+     * @param $url
+     *
+     * @throws \Exception
+     */
+    public function setUrl($url)
+    {
+        $this->setValue($url);
+    }
+}