Merge branch 'renovate/django-maintenance-mode-0.x' into 'master'

Update dependency django-maintenance-mode to ^0.18.0

See merge request !1116

pyproject.toml

@@ -65,7 +65,7 @@ libsass = "^0.22.0"
 colour = "^0.1.5"
 dynaconf = {version = "^3.1", extras = ["yaml", "toml", "ini"]}
 django-auth-ldap = { version = "^4.0", optional = true }
-django-maintenance-mode = "^0.16.3"
+django-maintenance-mode = "^0.18.0"
 django-ipware = "^4.0"
 django-impersonate = "^1.4"
 psycopg2 = "^2.8"