New dependencies

Author: arunchaganty

setup.py

@@ -78,7 +78,7 @@
     # your project is installed. For an analysis of "install_requires" vs pip's
     # requirements files see:
     # https://packaging.python.org/en/latest/requirements.html
-    install_requires=['corenlp-protobuf >= 3.8.0', 'requests >= 2.10.0'],
+    install_requires=['corenlp-protobuf >= 3.8.0', 'requests >= 2.10.0', 'six >= 1.9'],
 
     # List additional groups of dependencies here (e.g. development
     # dependencies). You can install these using the following syntax,