docs: code coverage badge

README.md

@@ -2,8 +2,10 @@
 [![License: MIT](https://img.shields.io/github/license/DennisGoldfarb/OpenAcquisition)](https://opensource.org/licenses/MIT)
 [![Documentation Status](https://readthedocs.org/projects/openacquisition/badge/?version=main)](https://openacquisition.readthedocs.io/en/main/?badge=main)
 ![Build](https://github.com/DennisGoldfarb/OpenAcquisition/actions/workflows/ci-cd.yml/badge.svg)
+[![codecov](https://codecov.io/gh/DennisGoldfarb/OpenAcquisition/branch/main/graph/badge.svg?token=CIMEPT9GCZ)](https://codecov.io/gh/DennisGoldfarb/OpenAcquisition)
 [![Version](https://img.shields.io/pypi/v/openacquisition)](https://pypi.org/project/openacquisition/)
 
+
 Python library to create data acquisition algorithms for mass spectrometers
 
 ## Requirements