Merge pull request #45 from hugovk/rm-sudo

CI: 'sudo: required' no longer required

Author: Benedikt Schmitt

.travis.yml

@@ -10,10 +10,8 @@ matrix:
     - python: "3.5"
     - python: "3.6"
     - python: "3.7"
-      sudo: required
       dist: xenial
     - python: "3.8-dev"
-      sudo: required
       dist: xenial
   allow_failures:
     - python: "3.8-dev"