Update tests, CI, readme for Django 2.2 release.

(Earlier Anymail releases work fine with Django 2.2, and have been
tested against it; this just makes everything official.)

Prefer Python 3.7 and Django 2.2 for "extra" tests (live integration,
optional packages, Django master).

.travis.yml

@@ -38,30 +38,29 @@ matrix:
     - { env: TOXENV=django20-pypy3-all, python: pypy3.5-6.0 }
     # Django 2.1: Python 3.5, 3.6, or 3.7
     - { env: TOXENV=django21-py35-all, python: 3.5 }
-    - { env: TOXENV=django21-py36-all RUN_LIVE_TESTS=true, python: 3.6 }
+    - { env: TOXENV=django21-py36-all, python: 3.6 }
     - { env: TOXENV=django21-py37-all, python: 3.7 }
     - { env: TOXENV=django21-pypy3-all, python: pypy3.5-6.0 }
     # Django 2.2: Python 3.5, 3.6, or 3.7
     - { env: TOXENV=django22-py35-all, python: 3.5 }
     - { env: TOXENV=django22-py36-all, python: 3.6 }
-    - { env: TOXENV=django22-py37-all, python: 3.7 }
+    - { env: TOXENV=django22-py37-all RUN_LIVE_TESTS=true, python: 3.7 }
     - { env: TOXENV=django22-pypy3-all, python: pypy3.5-6.0 }
     # Django development master (direct from GitHub source):
-    - { env: TOXENV=djangoMaster-py36-all, python: 3.6 }
+    - { env: TOXENV=djangoMaster-py37-all, python: 3.7 }
     # Install without optional extras (don't need to cover entire matrix)
-    - { env: TOXENV=django21-py37-none, python: 3.7 }
-    - { env: TOXENV=django21-py37-amazon_ses, python: 3.7 }
-    - { env: TOXENV=django21-py37-sparkpost, python: 3.7 }
+    - { env: TOXENV=django22-py37-none, python: 3.7 }
+    - { env: TOXENV=django22-py37-amazon_ses, python: 3.7 }
+    - { env: TOXENV=django22-py37-sparkpost, python: 3.7 }
 
   allow_failures:
-    - env: TOXENV=djangoMaster-py36-all
-      python: 3.6
+    - env: TOXENV=djangoMaster-py37-all
+      python: 3.7
 
 cache: pip
 
 install:
-  # avoid https://github.com/tox-dev/tox/issues/1160
-  - pip install tox!=3.7.0
+  - pip install tox
 
 script:
   - tox

README.rst

@@ -41,7 +41,7 @@ built-in `django.core.mail` package. It includes:
   with simplified, portable access to attachments and other inbound content
 
 Anymail is released under the BSD license. It is extensively tested against
-Django 1.11--2.1 (including Python 2.7, Python 3 and PyPy).
+Django 1.11--2.2 (including Python 2.7, Python 3 and PyPy).
 Anymail releases follow `semantic versioning <http://semver.org/>`_.
 
 .. END shared-intro

tox.ini

@@ -3,25 +3,25 @@ envlist =
     # Factors: django-python-extras
     # Test these environments first, to catch most errors early...
     lint
-    django21-py36-all
+    django22-py37-all
     django111-py27-all
     docs
     # ... then test all the other supported combinations:
-    django21-py{35,37,py3}-all
+    django22-py{35,36,py3}-all
+    django21-py{35,36,37,py3}-all
     django20-py{35,36,py3}-all
     django111-py{34,35,36,py}-all
     # ... then prereleases (if available):
-    django22-py{35,36,37,py3}-all
     djangoMaster-py{36,37}-all
     # ... then partial installation (limit extras):
-    django21-py37-{none,amazon_ses,sparkpost}
+    django22-py37-{none,amazon_ses,sparkpost}
 
 [testenv]
 deps =
     django111: django~=1.11.0
     django20: django~=2.0.0
     django21: django~=2.1.0
-    django22: django>=2.2a1
+    django22: django~=2.2.0
     djangoMaster: https://github.com/django/django/tarball/master
     # testing dependencies (duplicates setup.py tests_require, less optional extras):
     mock