Update the CI badge

Author: raszi

README.md

@@ -1,6 +1,6 @@
 # Mrkt
 
-[![Build Status](https://travis-ci.org/raszi/mrkt.svg?branch=master)](https://travis-ci.org/raszi/mrkt)
+[![Build Status](https://github.com/raszi/mrkt/actions/workflows/ruby.yml/badge.svg)](https://github.com/raszi/mrkt/actions/workflows/ruby.yml?query=branch%3Amaster)
 [![Code Climate](https://codeclimate.com/github/raszi/mrkt/badges/gpa.svg)](https://codeclimate.com/github/raszi/mrkt)
 [![Test Coverage](https://codeclimate.com/github/raszi/mrkt/badges/coverage.svg)](https://codeclimate.com/github/raszi/mrkt)
 [![Gem Version](https://badge.fury.io/rb/mrkt.svg)](https://badge.fury.io/rb/mrkt)