chore: update ci badge (#10)

Author: nrwiersma

README.md

@@ -1,7 +1,7 @@
 ![Logo](http://svg.wiersma.co.za/hamba/project?title=timex&tag=A%20fast%20clock%20source)
 
 [![Go Report Card](https://goreportcard.com/badge/github.com/hamba/timex)](https://goreportcard.com/report/github.com/hamba/timex)
-[![Build Status](https://travis-ci.com/hamba/timex.svg?branch=master)](https://travis-ci.com/hamba/timex)
+[![Build Status](https://github.com/hamba/timex/actions/workflows/test.yml/badge.svg)](https://github.com/hamba/timex/actions)
 [![Coverage Status](https://coveralls.io/repos/github/hamba/timex/badge.svg?branch=master)](https://coveralls.io/github/hamba/timex?branch=master)
 [![GoDoc](https://godoc.org/github.com/hamba/timex?status.svg)](https://godoc.org/github.com/hamba/timex)
 [![GitHub release](https://img.shields.io/github/release/hamba/timex.svg)](https://github.com/hamba/timex/releases)