Add build badge

Replay of this PR #344 which fixes the broken badge link

Signed-off-by: Anton Whalley <anton@venshare.com>

Author: No9

README.md

@@ -9,7 +9,7 @@
 </p>
 
 [![npm](https://img.shields.io/npm/v/llnode.svg?style=flat-square)](https://npmjs.org/package/llnode)
-![ci](https://img.shields.io/github/workflow/status/nodejs/llnode/push/main?style=flat-square)
+![ci](https://img.shields.io/github/workflow/status/nodejs/llnode/on%20push%20or%20pull_request/main?style=flat-square)
 [![coverage](https://img.shields.io/coveralls/github/nodejs/llnode/mmain?style=flat-square)](https://coveralls.io/github/nodejs/llnode)