Add RTD badge
@@ -27,6 +27,7 @@ of the [University of Passau](https://www.uni-passau.de).
[![Code style: black](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/ambv/black)
[![PyPI version](https://badge.fury.io/py/pynguin.svg)](https://badge.fury.io/py/pynguin)
[![Supported Python Versions](https://img.shields.io/pypi/pyversions/pynguin.svg)](https://gitlab.com/pynguin/pynguin)
+[![Documentation Status](https://readthedocs.org/projects/pynguin/badge/?version=latest)](https://pynguin.readthedocs.io/en/latest/?badge=latest)
![Pynguin Logo](docs/source/_static/pynguin-logo.png "Pynguin Logo")
