Update coveralls badge in readme

README.md

@@ -2,7 +2,7 @@
 [![Python 3.7](https://img.shields.io/badge/python-3.7-green.svg)](https://www.python.org/downloads/release/python-377/)
 [![Apache 2.0](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://www.apache.org/licenses/LICENSE-2.0)
 [![Build Status](https://app.travis-ci.com/Barski-lab/cwl-airflow.svg?branch=master)](https://app.travis-ci.com/Barski-lab/cwl-airflow)
-[![Coverage Status](https://coveralls.io/repos/github/Barski-lab/cwl-airflow/badge.svg?branch=master)](https://coveralls.io/github/Barski-lab/cwl-airflow?branch=master)
+[![Coverage Status](https://coveralls.io/repos/github/Barski-lab/cwl-airflow/badge.svg?branch=master&service=github)](https://coveralls.io/github/Barski-lab/cwl-airflow?branch=master)
 [![Downloads](https://pepy.tech/badge/cwl-airflow)](https://pepy.tech/project/cwl-airflow)