Pylint: abide by useless-object-inheritance warnings

Inheriting from object is a remainder of Python 2 habits and is just
clutter in Python 3.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/tests/scripts/test_generate_test_code.py b/tests/scripts/test_generate_test_code.py
index 6d7113e..e39b29b 100755
--- a/tests/scripts/test_generate_test_code.py
+++ b/tests/scripts/test_generate_test_code.py
@@ -294,7 +294,7 @@
         self.assertEqual(code, expected)
 
 
-class StringIOWrapper(StringIO, object):
+class StringIOWrapper(StringIO):
     """
     file like class to mock file object in tests.
     """