Add Github actions status

README.md

 # Archweb README
 
+[![Actions Status](https://github.com/archlinux/archweb/workflows/Github-Actions/badge.svg)](https://github.com/archlinux/archweb/actions)
 [![Build Status](https://travis-ci.com/archlinux/archweb.svg?branch=master)](https://travis-ci.com/archlinux/archweb)
 [![Coverage Status](https://coveralls.io/repos/github/archlinux/archweb/badge.svg?branch=master)](https://coveralls.io/github/archlinux/archweb?branch=master)