docs(README): fix GitHub Action Build Status URL

gr2m · web-flow · commit 9a4dadfc4817 · 2020-06-15T15:14:54.000-07:00
diff --git a/README.md b/README.md
@@ -3,7 +3,7 @@
 > Extendable client for GitHub's REST & GraphQL APIs
 
 [![@latest](https://img.shields.io/npm/v/@octokit/core.svg)](https://www.npmjs.com/package/@octokit/core)
-[![Build Status](https://github.com/octokit/core.js/workflows/Test/badge.svg)](https://github.com/octokit/core.js/actions?query=workflow%3ATest)
+[![Build Status](https://github.com/octokit/core.js/workflows/Test/badge.svg)](https://github.com/octokit/core.js/actions?query=workflow%3ATest+branch%3Amaster)
 
 <!-- toc -->
 
