Removed some imports of the six package

Author: Sylvain MARIE

pytest_cases/tests/pytest_extension/fixtures/fixture_plus_and_others/test_fixtures_parametrize_stereo.py

@@ -4,7 +4,7 @@
 # License: 3-clause BSD, <https://github.com/smarie/python-pytest-cases/blob/master/LICENSE>
 from itertools import product
 
-from six import string_types
+from pytest_cases.common_mini_six import string_types
 import pytest
 
 from pytest_cases import fixture

pytest_cases/tests/pytest_extension/meta/test_all.py

@@ -1,14 +1,12 @@
 import ast
 import os
 import shlex
-import sys
-from importlib import import_module
 
 import re
-from os.path import join, dirname, pardir, isdir, exists
+from os.path import join, dirname, isdir, exists
 
 import pytest
-from six import string_types
+from pytest_cases.common_mini_six import string_types
 
 # Make the list of all tests that we will have to execute (each in an independent pytest runner)
 THIS_DIR = dirname(__file__)