update python version testing

Carreau · mpacer · commit 889f822e4fed · 2018-05-18T10:32:16.000-07:00
diff --git a/.travis.yml b/.travis.yml
@@ -1,10 +1,10 @@
 language: python
 python:
     - "nightly"
-    - '3.6-dev'
+    - "3-7-dev"
+    - 3.6
     - 3.5
     - 3.4
-    - 3.3
     - 2.7
 sudo: false
 install:
