Updated .travis.yml

.travis.yml

 dist: trusty
 sudo: false
 
-language: python
-python:
-  - "2.7"
-  - "3.4"
-  - "3.5"
-  - "3.6"
+matrix:
+  include:
+    - python: 2.7
+    - python: 3.4
+    - python: 3.5
+    - python: 3.6
+    - python: 3.7
+      dist: xenial
+      sudo: true
 
 install:
   - pip install -r requirements.txt