Update .travis.yml

.travis.yml

@@ -3,15 +3,10 @@ matrix:
   fast_finish: true
   include:
     - python: "3.5"
-      env: TOXENV=py35
-    - python: "3.6"
-      env: TOXENV=py36
-    - python: "3.6-dev"
-      env: TOXENV=py36
 
 cache:
   directories:
     - $HOME/.cache/pip
 install: pip install -U tox
 language: python
-script: tox hassio_api
+script: tox