chg: Update readme

Author: Rafiot

Diff for: README.md

@@ -4,7 +4,7 @@
 
 [![Documentation Status](https://readthedocs.org/projects/pymisp/badge/?version=latest)](http://pymisp.readthedocs.io/?badge=latest)
 [![Coverage Status](https://coveralls.io/repos/github/MISP/PyMISP/badge.svg?branch=main)](https://coveralls.io/github/MISP/PyMISP?branch=main)
-[![Python 3.8](https://img.shields.io/badge/python-3.8+-blue.svg)](https://www.python.org/downloads/release/python-380/)
+[![Python 3.9](https://img.shields.io/badge/python-3.9+-blue.svg)](https://www.python.org/downloads/release/python-390/)
 [![PyPi version](https://img.shields.io/pypi/v/pymisp.svg)](https://pypi.python.org/pypi/pymisp/)
 [![Number of PyPI downloads](https://img.shields.io/pypi/dm/pymisp.svg)](https://pypi.python.org/pypi/pymisp/)
 
@@ -190,4 +190,3 @@ python -m pip install --no-index --no-deps packages/*.whl
 # License
 
 PyMISP is distributed under an [open source license](./LICENSE). A simplified 2-BSD license.
-