replace travis badge with github actions

Author: Kelly Selden

README.md

@@ -1,7 +1,7 @@
 # ember-cli-update
 
 [![npm version](https://badge.fury.io/js/ember-cli-update.svg)](https://badge.fury.io/js/ember-cli-update)
-[![Build Status](https://travis-ci.org/ember-cli/ember-cli-update.svg?branch=master)](https://travis-ci.org/ember-cli/ember-cli-update)
+![](https://github.com/ember-cli/ember-cli-update/workflows/CI/badge.svg)
 [![Build status](https://ci.appveyor.com/api/projects/status/iguxxyxkiu9kyeyo/branch/master?svg=true)](https://ci.appveyor.com/project/embercli/ember-cli-update/branch/master)
 
 Update [Ember CLI](https://ember-cli.com/) [Ember.js](https://www.emberjs.com/) apps and addons (and [Glimmer.js](https://glimmerjs.com/) apps)