readme: added pipeline badge

README.md

@@ -1,6 +1,7 @@
 # python-cc1101
 
 [![Code style: black](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/psf/black)
+[![CI Pipeline Status](https://github.com/fphammerle/python-cc1101/workflows/tests/badge.svg)](https://github.com/fphammerle/python-cc1101/actions)
 [![Last Release](https://img.shields.io/pypi/v/cc1101.svg)](https://pypi.org/project/cc1101/#history)
 [![Compatible Python Versions](https://img.shields.io/pypi/pyversions/cc1101.svg)](https://pypi.org/project/cc1101/)