docs: update badge to GitHub actions

Author: felixfbecker

README.md

@@ -2,7 +2,7 @@
 
 [![npm](https://img.shields.io/npm/v/@sourcegraph/create.svg)](https://www.npmjs.com/package/@sourcegraph/create)
 [![downloads](https://img.shields.io/npm/dt/@sourcegraph/create.svg)](https://www.npmjs.com/package/@sourcegraph/create)
-[![build](https://travis-ci.org/sourcegraph/create.svg?branch=master)](https://travis-ci.org/sourcegraph/create)
+[![build](https://img.shields.io/github/workflow/status/sourcegraph/create/build/master)](https://github.com/sourcegraph/create/actions?query=branch%3Amaster+workflow%3Abuild)
 [![code style: prettier](https://img.shields.io/badge/code_style-prettier-ff69b4.svg)](https://github.com/prettier/prettier)
 [![semantic-release](https://img.shields.io/badge/%20%20%F0%9F%93%A6%F0%9F%9A%80-semantic--release-e10079.svg)](https://github.com/semantic-release/semantic-release)