readme: updated badge

Author: dg

readme.md

@@ -2,7 +2,7 @@ Nette Utility Classes
 =====================
 
 [![Downloads this Month](https://img.shields.io/packagist/dm/nette/utils.svg)](https://packagist.org/packages/nette/utils)
-[![Build Status](https://travis-ci.org/nette/utils.svg?branch=master)](https://travis-ci.org/nette/utils)
+[![Tests](https://github.com/nette/utils/workflows/Tests/badge.svg?branch=master)](https://github.com/nette/utils/actions)
 [![Coverage Status](https://coveralls.io/repos/github/nette/utils/badge.svg?branch=master)](https://coveralls.io/github/nette/utils?branch=master)
 [![Latest Stable Version](https://poser.pugx.org/nette/utils/v/stable)](https://github.com/nette/utils/releases)
 [![License](https://img.shields.io/badge/license-New%20BSD-blue.svg)](https://github.com/nette/utils/blob/master/license.md)