Update noxfile.py

Author: abbrowne126

noxfile.py

@@ -34,7 +34,7 @@
 
 MYPY_VERSION = "mypy==1.10.0"
 
-DEFAULT_PYTHON_VERSION = "3.10"
+DEFAULT_PYTHON_VERSION = "3.13"
 
 UNIT_TEST_PYTHON_VERSIONS: List[str] = [
     "3.7",
@@ -432,7 +432,7 @@ def docfx(session):
     )
 
 
-@nox.session(python="3.13")
+@nox.session(python=DEFAULT_PYTHON_VERSION)
 @nox.parametrize(
     "protobuf_implementation",
     ["python", "upb", "cpp"],