docs: fix build badge

Author: felixfbecker

README.md

@@ -1,6 +1,6 @@
 # CodeIntellify
 
-[![build](https://badge.buildkite.com/da1855cc6c9b02ddfa1df69599aacecd1317db8f6765edfa8b.svg?branch=master)](https://buildkite.com/sourcegraph/codeintellify)
+[![build](https://travis-ci.org/sourcegraph/codeintellify.svg?branch=master)](https://travis-ci.org/sourcegraph/codeintellify)
 [![codecov](https://codecov.io/gh/sourcegraph/codeintellify/branch/master/graph/badge.svg?token=1Xk7sdvG0y)](https://codecov.io/gh/sourcegraph/codeintellify)
 [![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)