Test on python 3.7

Author: untitaker

.travis.yml

@@ -4,6 +4,7 @@ python:
 - '2.7'
 - '3.5'
 - '3.6'
+- '3.7'
 cache: pip
 install: pip install -U tox setuptools_scm
 env:
@@ -13,9 +14,9 @@ env:
   - TOXENV=py-pytestlatest
 matrix:
   include:
-  - python: '3.6'
+  - python: '3.7'
     env: TOXENV=flakes
-  - python: '3.6'
+  - python: '3.7'
     env: TOXENV=readme
 
     # piggyback on existing build for releases