chore: update generated noxfile.py to cater for grafeas

Author: parthea

gapic/templates/noxfile.py.j2

@@ -143,7 +143,11 @@ def lint(session):
         *LINT_PATHS,
     )
 
-    session.run("flake8", "google", "tests")
+{% if api.naming.module_namespace %}
+    session.run("flake8", "{{ api.naming.module_namespace[0] }}", "tests")
+{% else %}
+    session.run("flake8", "{{ api.naming.versioned_module_name }}, "tests")
+{% endif %}
 
 
 @nox.session(python=DEFAULT_PYTHON_VERSION)