Must use Python 3.9 or above

Fixes #14

Author: JackKelly

README.md

@@ -14,6 +14,8 @@ pip install -e .
 
 Alternatively, you can also install a usually older version through ```pip install metnet```
 
+Please ensure that you're using Python version 3.9 or above.
+
 ## Data
 
 While the exact training data used for both MetNet and MetNet-2 haven't been released, the papers do go into some detail as to the inputs, which were GOES-16 and MRMS precipitation data, as well as the time period covered. We will be making those splits available, as well as a larger dataset that covers a longer time period, with [HuggingFace Datasets](https://huggingface.co/datasets/openclimatefix/goes-mrms)!