remove py_lib config

Author: ohmayr

owlbot.py

@@ -99,8 +99,6 @@ def get_staging_dirs(
 templated_files = common.py_library(
     microgenerator=True,
     split_system_tests=True,
-    default_python_version="3.13",
-    system_test_python_versions=["3.13"],
     # six required by (but not installed by) google-cloud-core < v2.0.0
     unit_test_external_dependencies=["six"],
     system_test_external_dependencies=["six"],