Update setup.py

drop support for python 2.x
requires notebook >=6.0

Author: demotu

setup.py

@@ -6,8 +6,6 @@
 # Imports
 # -----------------------------------------------------------------------------
 
-from __future__ import print_function
-
 import os
 from glob import glob
 
@@ -65,10 +63,10 @@ def main():
             'jupyter_contrib_core >=0.3.3',
             'jupyter_core',
             'jupyter_highlight_selected_word >=0.1.1',
-            'jupyter_latex_envs >=1.3.8',
+            'jupyter_latex_envs >=1.4.0',
             'jupyter_nbextensions_configurator >=0.4.0',
             'nbconvert >=6.0',
-            'notebook >=4.0',
+            'notebook >=6.0',
             'pyyaml',
             'tornado',
             'traitlets >=4.1',