📝 Update readme badges

Signed-off-by: burgholzer <burgholzer@me.com>

README.md

@@ -1,6 +1,9 @@
+[![PyPI](https://img.shields.io/pypi/v/mqt.core?logo=pypi&style=flat-square)](https://pypi.org/project/mqt.core/)
 ![OS](https://img.shields.io/badge/os-linux%20%7C%20macos%20%7C%20windows-blue?style=flat-square)
 [![License: MIT](https://img.shields.io/badge/license-MIT-blue.svg?style=flat-square)](https://opensource.org/licenses/MIT)
-[![CI](https://img.shields.io/github/actions/workflow/status/cda-tum/mqt-core/ci.yml?branch=main&style=flat-square&logo=github&label=CI)](https://github.com/cda-tum/mqt-core/actions/workflows/ci.yml)
+[![CI](https://img.shields.io/github/actions/workflow/status/cda-tum/mqt-core/ci.yml?branch=main&style=flat-square&logo=github&label=ci)](https://github.com/cda-tum/mqt-core/actions/workflows/ci.yml)
+[![CD](https://img.shields.io/github/actions/workflow/status/cda-tum/mqt-core/cd.yml?branch=main&style=flat-square&logo=github&label=cd)](https://github.com/cda-tum/mqt-core/actions/workflows/cd.yml)
+[![Documentation](https://img.shields.io/readthedocs/mqt-core?logo=readthedocs&style=flat-square)](https://mqt.readthedocs.io/projects/core)
 [![codecov](https://img.shields.io/codecov/c/github/cda-tum/mqt-core?style=flat-square&logo=codecov)](https://codecov.io/gh/cda-tum/mqt-core)
 
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