Remove default 'dist: xenial' from Travis CI configuration (#813)
Remove default 'dist: xenial' from Travis CI configuration (#813)

Since May 2019, Travis has used Ubuntu Xenial 16.04 as the default
Travis CI build environment.

For additional details, see:

https://blog.travis-ci.com/2019-04-15-xenial-default-build-environment
jschneier/django-storages