🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

Author: gcf-owl-bot[bot]

noxfile.py

@@ -32,7 +32,7 @@
 ISORT_VERSION = "isort==5.11.0"
 LINT_PATHS = ["docs", "google", "tests", "noxfile.py", "setup.py"]
 
-DEFAULT_PYTHON_VERSION = "3.12"
+DEFAULT_PYTHON_VERSION = "3.8"
 
 DEFAULT_MOCK_SERVER_TESTS_PYTHON_VERSION = "3.12"
 UNIT_TEST_PYTHON_VERSIONS: List[str] = [