Keep number of test case up to date

README.md

@@ -5,7 +5,7 @@
 <a href="https://travis-ci.com/Colin-b/keepachangelog"><img alt="Build status" src="https://api.travis-ci.com/Colin-b/keepachangelog.svg?branch=master"></a>
 <a href="https://travis-ci.com/Colin-b/keepachangelog"><img alt="Coverage" src="https://img.shields.io/badge/coverage-100%25-brightgreen"></a>
 <a href="https://github.com/psf/black"><img alt="Code style: black" src="https://img.shields.io/badge/code%20style-black-000000.svg"></a>
-<a href="https://travis-ci.com/Colin-b/keepachangelog"><img alt="Number of tests" src="https://img.shields.io/badge/tests-22 passed-blue"></a>
+<a href="https://travis-ci.com/Colin-b/keepachangelog"><img alt="Number of tests" src="https://img.shields.io/badge/tests-28 passed-blue"></a>
 <a href="https://pypi.org/project/keepachangelog/"><img alt="Number of downloads" src="https://img.shields.io/pypi/dm/keepachangelog"></a>
 </p>