Fixes CircleCI badge refs #2983

Author: JJ

README.md

@@ -1,6 +1,6 @@
 # Official Documentation of Perl 6
 
-[![Build Status](https://travis-ci.org/perl6/doc.svg?branch=master)](https://travis-ci.org/perl6/doc) [![artistic](https://img.shields.io/badge/license-Artistic%202.0-blue.svg?style=flat)](https://opensource.org/licenses/Artistic-2.0) [![Run Status](https://api.shippable.com/projects/591e99923f2f790700098a30/badge?branch=master)](https://app.shippable.com/github/perl6/doc) [![CircleCI](https://circleci.com/gh/perl6/doc.svg?style=svg)](https://circleci.com/gh/perl6/doc)
+[![Build Status](https://travis-ci.org/perl6/doc.svg?branch=master)](https://travis-ci.org/perl6/doc) [![artistic](https://img.shields.io/badge/license-Artistic%202.0-blue.svg?style=flat)](https://opensource.org/licenses/Artistic-2.0) [![Run Status](https://api.shippable.com/projects/591e99923f2f790700098a30/badge?branch=master)](https://app.shippable.com/github/perl6/doc) [![CircleCI](https://circleci.com/gh/perl6/doc/tree/master.svg?style=svg)](https://circleci.com/gh/perl6/doc/tree/master)
 
 An HTML version of this documentation can be found
 at [https://docs.perl6.org/](https://docs.perl6.org/) and also