[ticket/16549] PHPUnit function declarations tiny cleanup

PHPBB3-16549

tests/version/version_helper_remote_test.php

@@ -17,7 +17,7 @@ class version_helper_remote_test extends \phpbb_test_case
 	protected $cache;
 	protected $version_helper;
 
-	public function setUp(): void
+	protected function setUp(): void
 	{
 		parent::setUp();