Update README.md (#40587)

Author: kristapratico

README.md

@@ -12,7 +12,7 @@ You can find service libraries in the `/sdk` directory.
 
 ### Prerequisites
 
-The client libraries are supported on Python 3.8 or later. For more details, please read our page on [Azure SDK for Python version support policy](https://github.com/Azure/azure-sdk-for-python/wiki/Azure-SDKs-Python-version-support-policy).
+The client libraries are supported on Python 3.9 or later. For more details, please read our page on [Azure SDK for Python version support policy](https://github.com/Azure/azure-sdk-for-python/wiki/Azure-SDKs-Python-version-support-policy).
 
 ## Packages available