Drop Python 3.8 support in typeshed utilities (#13774)

scripts/sync_protobuf/_utils.py

@@ -2,8 +2,9 @@ from __future__ import annotations
 
 import subprocess
 import sys
+from collections.abc import Iterable
 from http.client import HTTPResponse
-from typing import TYPE_CHECKING, Iterable
+from typing import TYPE_CHECKING
 from urllib.request import urlopen
 from zipfile import ZipFile