Update README.md

Author: chrisjsewell

README.md

@@ -1,9 +1,12 @@
 # markdown-it-py
 
 ![Github-DI][github-ci]
+[![PyPI][pypi-badge]][pypi-link]
 [![Code style: black][black-badge]][black-link]
 
 [github-ci]: https://github.com/ExecutableBookProject/markdown-it-py/workflows/Python%20package/badge.svg
+[pypi-badge]: https://img.shields.io/pypi/v/markdown-it-py.svg
+[pypi-link]: https://pypi.org/project/markdown-it-py
 [black-badge]: https://img.shields.io/badge/code%20style-black-000000.svg
 [black-link]: https://github.com/ambv/black