require configparser only in python < 3.6 (databricks#287)

configparser comes in default python >= 3.6

Author: acxz

setup.py

@@ -38,7 +38,7 @@
         'requests>=2.17.3',
         'tabulate>=0.7.7',
         'six>=1.10.0',
-        'configparser >= 0.3.5',
+        'configparser>=0.3.5;python_version < "3.6"',
     ],
     entry_points='''
         [console_scripts]