Add non-voting job to test Django 5.2

Django 5.2 was released a few months ago as the latest LTS. Add a new
non-voting job to run tests with it, so that we can catch compatibility
problems earlier.

Change-Id: I359e819f556cb2a4b07e8a225b3385ae430f1a4f
Signed-off-by: Takashi Kajinami <kajinamit@oss.nttdata.com>

.zuul.d/django-jobs.yaml

@@ -32,6 +32,13 @@
     vars:
       django_version: '>=4.2,<4.3'
 
+- job:
+    name: horizon-tox-python3-django52
+    parent: horizon-tox-python3-django
+    voting: false
+    vars:
+      django_version: '>=5.2,<5.3'
+
 - project-template:
     name: horizon-non-primary-django-jobs
     description: |
@@ -47,6 +54,7 @@
         # only one version of Django covered by the default job.
         # Just comment it out for such case.
         - horizon-tox-python3-django42
+        - horizon-tox-python3-django52
     gate:
       jobs:
         # Default python job in openstack-python3-antelope-jobs(-horizon)

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 minversion = 4.4
-envlist = pep8,py3,releasenotes,npm,py3-dj42
+envlist = pep8,py3,releasenotes,npm,py3-dj{42,52}
 
 [testenv]
 usedevelop = True
@@ -21,6 +21,7 @@ deps =
   hacking>=7.0.0,<7.1.0 # Apache-2.0
 commands =
   dj42: pip install django>=4.2,<4.3
+  dj52: pip install django>=5.2,<5.3
   find . -type f -name "*.pyc" -delete
   bash {toxinidir}/tools/unit_tests.sh {toxinidir} {posargs}