Update minimum supported version of python in docs

Author: Huluti

docs/generators/python.md

@@ -10,7 +10,7 @@ title: Documentation for the python Generator
 | generator stability | STABLE | |
 | generator type | CLIENT | |
 | generator language | Python | |
-| generator language version | 3.7+ | |
+| generator language version | 3.8+ | |
 | generator default templating engine | mustache | |
 | helpTxt | Generates a Python client library. | |