Update tox.ini

tests for python versions: 3.6, 3.7, 3.8
tests only for notebook 6.0.0

Author: demotu

tox.ini

@@ -6,16 +6,15 @@ envlist =
     clean,
     check,
     lint,
-    {py27,py36}-notebook{44,54,55},
+    {py36,py37,py38}-notebook{60},
     report,
 
 [testenv]
 basepython =
     pypy: {env:TOXPYTHON:pypy}
-    py27: {env:TOXPYTHON:python2.7}
     py36: {env:TOXPYTHON:python3.6}
     py37: {env:TOXPYTHON:python3.7}
-    {spell}: {env:TOXPYTHON:python2.7}
+    {py38,spell}: {env:TOXPYTHON:python3.8}
     {appveyorartifacts,lint,check}: {env:TOXPYTHON:python3}
     {condarecipe}: {env:TOXPYTHON:python3}
     {clean,codecov,coveralls,report}: {env:TOXPYTHON:python3}
@@ -29,12 +28,10 @@ usedevelop = false
 deps =
     coverage>=4.2
     jupyter_highlight_selected_word>=0.0.5
-    jupyter_latex_envs>=1.3.4
+    jupyter_latex_envs>=1.4.0
     mock
     nose
-    notebook44: https://github.com/jupyter/notebook/archive/4.4.0.zip
-    notebook54: https://github.com/jupyter/notebook/archive/5.4.0.zip
-    notebook55: https://github.com/jupyter/notebook/archive/5.5.0.zip
+    notebook60: https://github.com/jupyter/notebook/archive/6.0.0.zip
     notebookmaster: https://github.com/jupyter/notebook/archive/master.zip
     notebook: notebook
 commands =