Drop artefact for python2 support

Remove python2 compatible syntax in tests and remove a packaging option in `setup.cfg` (c.f. https://packaging.python.org/en/latest/guides/dropping-older-python-versions/)

setup.cfg

@@ -1,9 +1,3 @@
-[bdist_wheel]
-# This flag says that the code is written to work on both Python 2 and Python
-# 3. If at all possible, it is good practice to do this. If you cannot, you
-# will need to generate wheels for each Python version that you support.
-python-tag=py3
-
 [mypy]
 
 # For details on each flag, please see the mypy documentation at:

tests/tests.py

@@ -12,11 +12,7 @@
 except ImportError:
     pass
 
-try:
-    from StringIO import StringIO  # noqa
-except ImportError:
-    # Python 3 Support
-    from io import StringIO
+from io import StringIO
 
 sys.path.append('src/python-json-logger')
 from pythonjsonlogger import jsonlogger
@@ -78,7 +74,6 @@ def testAddStaticFields(self):
         self.assertEqual(logJson["log_stream"], "kafka")
         self.assertEqual(logJson["message"], msg)
 
-
     def testFormatKeys(self):
         supported_keys = [
             'asctime',
@@ -258,6 +253,7 @@ def encode_complex(z):
         msg = self.buffer.getvalue()
         self.assertEqual(msg, "{\"message\": \" message\", \"special\": [3.0, 8.0]}\n")
 
+
 if __name__ == '__main__':
     if len(sys.argv[1:]) > 0:
         if sys.argv[1] == 'xml':