update min required python version

Author: antoine-galataud

README.md

@@ -6,7 +6,7 @@ This project implements a gym environment that handles [EnergyPlus](https://ener
 for Reinforcement Learning (RL) experiments, using the EnergyPlus Python API.
 It also provides a set of examples and tools to train RL agents.
 
-Requires Python 3.8+, EnergyPlus 9.3+
+Requires Python 3.9+, EnergyPlus 9.3+
 
 ## Setup