README.md: add link to CI results

Author: daurnimator

README.md

@@ -17,7 +17,7 @@ Can be found at [https://daurnimator.github.io/lua-http/](https://daurnimator.gi
 
 ## Status
 
-![Build Status](https://github.com/daurnimator/lua-http/workflows/ci/badge.svg)
+[![Build Status](https://github.com/daurnimator/lua-http/workflows/ci/badge.svg)](https://github.com/daurnimator/lua-http/actions?query=workflow%3Aci)
 [![Coverage Status](https://coveralls.io/repos/daurnimator/lua-http/badge.svg?branch=master&service=github)](https://coveralls.io/github/daurnimator/lua-http?branch=master)
 [![CII Best Practices](https://bestpractices.coreinfrastructure.org/projects/108/badge)](https://bestpractices.coreinfrastructure.org/projects/108)