Set django-upgrade to target Django 4.2 (jazzband#729)

* Remove tests against Django 3.2

* Upgrade Django-Upgrade pre-commit to target Django 4.2

Author: albertyw

.pre-commit-config.yaml

@@ -55,7 +55,7 @@ repos:
   rev: '1.20.0'
   hooks:
   - id: django-upgrade
-    args: [--target-version, '3.2']
+    args: [--target-version, '4.2']
 - repo: https://github.com/hhatto/autopep8
   rev: 'v2.3.1'
   hooks: