misc: change pyupgrade target version to 3.9 (#75442)

.pre-commit-config.yaml

@@ -12,10 +12,10 @@ repos:
     - id: isort
       args: ['--profile', 'black', '--line-length', '110']
 -   repo: https://github.com/asottile/pyupgrade
-    rev: v3.1.0
+    rev: v3.3.1
     hooks:
     - id: pyupgrade
-      args: ['--keep-percent-format', '--py37-plus']
+      args: ['--keep-percent-format', '--py39-plus']
 -   repo: https://github.com/adamchainz/django-upgrade
     rev: 1.13.0
     hooks:

chrono/utils/timezone.py

@@ -24,7 +24,7 @@ from django.conf import settings
 utc = zoneinfo.ZoneInfo('UTC')
 
 
-@functools.lru_cache()
+@functools.lru_cache
 def get_default_timezone():
     """
     Return the default time zone as a tzinfo instance.