Update badge in README.md to link to CircleCI (#4104)

* Update README.md

* Update README.md

* Update README.md

Co-Authored-By: Ran Byron <ranbena@gmail.com>

* Update README.md

README.md

@@ -4,7 +4,7 @@
 
 [![Documentation](https://img.shields.io/badge/docs-redash.io/help-brightgreen.svg)](https://redash.io/help/)
 [![Datree](https://s3.amazonaws.com/catalog.static.datree.io/datree-badge-20px.svg)](https://datree.io/?src=badge)
-![Build Status](https://circleci.com/gh/getredash/redash.png?circle-token=8a695aa5ec2cbfa89b48c275aea298318016f040)
+[![Build Status](https://circleci.com/gh/getredash/redash.png?style=shield&circle-token=8a695aa5ec2cbfa89b48c275aea298318016f040)](https://circleci.com/gh/getredash/redash/tree/master)
 
 **_Redash_** is our take on freeing the data within our company in a way that will better fit our culture and usage patterns.