Merge pull request #1151 from jdufresne/dj22

Test against for Django 2.2 release

Author: matthiask

tox.ini

@@ -16,7 +16,7 @@ deps =
     dj111: Django>=1.11,<2.0
     dj20: Django>=2.0,<2.1
     dj21: Django>=2.1,<2.2
-    dj22: Django>=2.2b1,<3.0
+    dj22: Django>=2.2,<3.0
     djmaster: https://github.com/django/django/archive/master.tar.gz
     coverage
     django_jinja