Update test badge

(cherry picked from commit 39dd7c3)

README.md

@@ -4,7 +4,7 @@ Phug
 
 [![Latest Stable Version](https://poser.pugx.org/phug/phug/v/stable.png)](https://packagist.org/packages/phug/phug)
 [![Monthly Downloads](https://poser.pugx.org/phug/phug/d/monthly)](https://packagist.org/packages/phug/phug)
-[![Build Status](https://travis-ci.org/phug-php/phug.svg?branch=master)](https://travis-ci.org/phug-php/phug)
+[![Tests](https://github.com/phug-php/phug/actions/workflows/tests.yml/badge.svg)](https://github.com/phug-php/phug/actions/workflows/tests.yml)
 [![Test Coverage](https://codeclimate.com/github/phug-php/phug/badges/coverage.svg)](https://codeclimate.com/github/phug-php/phug/coverage)
 [![Code Climate](https://codeclimate.com/github/phug-php/phug/badges/gpa.svg)](https://codeclimate.com/github/phug-php/phug)
 [![StyleCI](https://styleci.io/repos/74360844/shield?branch=master)](https://styleci.io/repos/74360844)