Update owlbot.py

Co-authored-by: Anthonios Partheniou <partheniou@google.com>

Author: chalmerlowe

owlbot.py

@@ -104,8 +104,8 @@ def get_staging_dirs(
     system_test_external_dependencies=["six"],
     cov_level=100,
     unit_test_python_versions=["3.8", "3.9", "3.10", "3.11", "3.12", "3.13", "3.14"],
-    default_python_version="3.10",
-    system_test_python_versions=["3.12"],
+    default_python_version="3.14",
+    system_test_python_versions=["3.14"],
 )
 s.move(
     templated_files,