php8 support

tests/Internal/Epub/EpubWriter.php

@@ -1,5 +1,14 @@
 <?php
 
+declare(strict_types=1);
+
+/*
+ * This file is part of the nelexa/zip package.
+ * (c) Ne-Lexa <https://github.com/Ne-Lexa/php-zip>
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
 namespace PhpZip\Tests\Internal\Epub;
 
 use PhpZip\Constants\ZipCompressionMethod;
@@ -19,7 +28,7 @@ class EpubWriter extends ZipWriter
     /**
      * @throws ZipUnsupportMethodException
      */
-    protected function beforeWrite()
+    protected function beforeWrite(): void
     {
         parent::beforeWrite();
 
@@ -35,7 +44,7 @@ class EpubWriter extends ZipWriter
         $this->sortEntries();
     }
 
-    private function sortEntries()
+    private function sortEntries(): void
     {
         $this->zipContainer->sortByEntry(
             static function (ZipEntry $a, ZipEntry $b) {