Update Travis config with warnings and info on build

.travis.yml

@@ -1,5 +1,5 @@
-sudo: false
 language: python
+os: linux
 dist: xenial
 services:
   - mysql
@@ -8,7 +8,7 @@ services:
 git:
   depth: false
 
-matrix:
+jobs:
   include:
     - python: 2.7
       env: TOXENV=py27-django111