Reflect support for PHP 8.1 in the README

Author: marijnvanwezel

README.md

@@ -3,10 +3,10 @@ PHP Parser
 
 [![Coverage Status](https://coveralls.io/repos/github/nikic/PHP-Parser/badge.svg?branch=master)](https://coveralls.io/github/nikic/PHP-Parser?branch=master)
 
-This is a PHP 5.2 to PHP 8.0 parser written in PHP. Its purpose is to simplify static code analysis and
+This is a PHP 5.2 to PHP 8.1 parser written in PHP. Its purpose is to simplify static code analysis and
 manipulation.
 
-[**Documentation for version 4.x**][doc_master] (stable; for running on PHP >= 7.0; for parsing PHP 5.2 to PHP 8.0).
+[**Documentation for version 4.x**][doc_master] (stable; for running on PHP >= 7.0; for parsing PHP 5.2 to PHP 8.1).
 
 [Documentation for version 3.x][doc_3_x] (unsupported; for running on PHP >= 5.5; for parsing PHP 5.2 to PHP 7.2).