[NFC] python_format: Use a valid target version

AnthonyLatsis · AnthonyLatsis · commit 34b6eac727fd · 2022-11-22T19:46:15.000+03:00
diff --git a/utils/python_format.py b/utils/python_format.py
@@ -137,7 +137,7 @@ def main():
         "-m",
         "black",
         "--target-version",
-        "py27",
+        "py38",
     ]
 
     if args.check:
