Fix various compatibility issues with PHP 8

libs/ical/Component/Timezone.php

@@ -0,0 +1,57 @@
+<?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\Component;
+
+use Eluceo\iCal\Component;
+use Eluceo\iCal\PropertyBag;
+
+/**
+ * Implementation of the TIMEZONE component.
+ */
+class Timezone extends Component
+{
+    /**
+     * @var string
+     */
+    protected $timezone;
+
+    public function __construct($timezone)
+    {
+        $this->timezone = $timezone;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getType()
+    {
+        return 'VTIMEZONE';
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function buildPropertyBag()
+    {
+        $propertyBag = new PropertyBag();
+
+        $propertyBag->set('TZID', $this->timezone);
+        $propertyBag->set('X-LIC-LOCATION', $this->timezone);
+
+        return $propertyBag;
+    }
+
+    public function getZoneIdentifier()
+    {
+        return $this->timezone;
+    }
+}