Update dependency gunicorn to v23 [SECURITY]

Author: renovate[bot]

pyproject.toml

@@ -24,7 +24,7 @@ dependencies = [
     'django-colorfield==0.11.0',
     'django-ical==1.9.2',
     'django-phonenumber-field[phonenumberslite]==7.3.0',
-    'gunicorn==21.2.0',
+    'gunicorn==23.0.0',
     'holidays==0.40',
     'icalendar==5.0.11',
     'Pillow==10.4.0',