Drop Django 2.2 support

Django 2.2 support was dropped. Django 2.2 ends its extended support
in April 2022[1]. Considering this, horizon dropped Django 2.2 support
and use Django 3.2 as default version of Django.

It also updates the python version from py38 to py39 for
"horizon-non-primary-django-jobs" and
"horizon-tox-python3-django" project template because py36
and py39 are now runtime for the Yoga cycle[2]. So I have updated it to
py39.

[1] https://www.djangoproject.com/download/
[2] https://review.opendev.org/c/openstack/governance/+/820195

Change-Id: I8886f12f7e51b721ac5123070086d5dcfefe4e72

.zuul.d/django-jobs.yaml

@@ -17,30 +17,22 @@
     pre-run: playbooks/horizon-tox-django/pre.yaml
     run: playbooks/horizon-tox-django/run.yaml
     vars:
-      tox_envlist: py38
+      tox_envlist: py39
     required-projects:
       - name: openstack/horizon
 
-- job:
-    name: horizon-tox-python3-django32
-    parent: horizon-tox-python3-django
-    vars:
-      django_version: '>=3.2,<3.3'
-
 - project-template:
     name: horizon-non-primary-django-jobs
     description: |
       Run unit tests with non-primary Django versions.
     check:
       jobs:
-        # Currently we only support Django 2.2, so there is no need
+        # Currently we only support Django 3.2, so there is no need
         # to run tests with different versions of Django.
         # We specify a job in openstack-python3-yoga-jobs(-horizon)
         # to keep this project template as it is used in horizon plugins.
         # NOTE: We keep it as a template even though it is not used now.
-        - openstack-tox-py38
-        - horizon-tox-python3-django32
+        - openstack-tox-py39
     gate:
       jobs:
-        - openstack-tox-py38
-        - horizon-tox-python3-django32
+        - openstack-tox-py39

doc/source/contributor/testing.rst

@@ -107,11 +107,10 @@ when a test fails you can use::
 
   $ tox -e py37 -- --pdb
 
-py3-dj111, py3-dj21, py3-dj22
+py3-dj32
 -----------------------------
 
-Runs the Python unit tests against Django 1.11, Django 2.1 and Django 2.2
-respectively
+Runs the Python unit tests against Django 3.2.
 
 py36
 ----

doc/source/install/system-requirements.rst

@@ -6,10 +6,8 @@ The Ussuri release of horizon has the following dependencies.
 
 * Python 3.6 or 3.7
 
-* Django 2.2
+* Django 3.2
 
-  * Django 3.2 support is experimental as of Xena release.
-    (Yoga release will use Django 3.2 as the primary Django version.)
   * Django support policy is documented at :ref:`django_support`.
 
 * An accessible `keystone <https://docs.openstack.org/keystone/latest/>`_ endpoint

lower-constraints.txt

@@ -15,7 +15,7 @@ cryptography==3.0
 debtcollector==1.2.0
 decorator==4.4.2
 deprecation==1.0
-Django==2.2
+Django==3.2
 django-appconf==1.0.5
 django-compressor==2.4.1
 django-debreach==1.4.2

releasenotes/notes/drop-django22-support-d0e2dea1509228a2.yaml

@@ -0,0 +1,6 @@
+---
+upgrade:
+  - |
+    Django 2.2 support was dropped. Django 2.2 ends its extended support
+    in April 2022. Considering this horizon dropped Django 2.2 support
+    and uses Django 3.2 as default.

requirements.txt

@@ -12,7 +12,7 @@ pbr>=5.5.0 # Apache-2.0
 # Horizon Core Requirements
 Babel>=2.6.0 # BSD
 debtcollector>=1.2.0 # Apache-2.0
-Django>=2.2,<3.3 # BSD
+Django>=3.2,<3.3 # BSD
 django-compressor>=2.4.1 # MIT
 django-debreach>=1.4.2 # BSD License (2 clause)
 django-pyscss>=2.0.2 # BSD License (2 clause)