Add PyPi badge

Author: neuromechanist

docs/index.md

@@ -1,5 +1,6 @@
 # Welcome to EMGIO
 
+[![PyPI version](https://badge.fury.io/py/emgio.svg)](https://badge.fury.io/py/emgio)
 [![Tests](https://github.com/neuromechanist/emgio/actions/workflows/tests.yml/badge.svg)](https://github.com/neuromechanist/emgio/actions/workflows/tests.yml)
 [![codecov](https://codecov.io/gh/neuromechanist/emgio/branch/main/graph/badge.svg?token=63EDIA9TWD)](https://codecov.io/gh/neuromechanist/emgio)
 
@@ -77,4 +78,4 @@ This documentation is organized as follows:
 
 ## License
 
-This project is licensed under the BSD 3-Clause License. 
+This project is licensed under the BSD 3-Clause License.