Updated .travis.yml

.travis.yml

@@ -1,13 +1,22 @@
-dist: xenial
-sudo: required
+sudo: false
 language: python
-python: 3.7
+python: 3.5
 cache: pip
 env:
   - TOX_ENV=py27
+  - TOX_ENV=py34
   - TOX_ENV=py35
-  - TOX_ENV=py36
-  - TOX_ENV=py37
+matrix:
+  include:
+    - python: "3.6"
+      env:
+        - TOX_ENV=py36
+    - python: "3.7"
+      env:
+        - TOX_ENV=py37
+      dist: xenial
+      language: python
+      sudo: required
 install:
   - pip install tox
 script: