Update kiwitcms-tenants from 2.5.2 to 2.6.0

Author: pyup-bot

requirements.txt

@@ -3,7 +3,7 @@ django-python3-ldap==0.15.5
 django-ses==3.5.2
 dj-database-url==2.1.0
 kiwitcms-github-app==1.5.1
-kiwitcms-tenants==2.5.2
+kiwitcms-tenants==2.6.0
 kiwitcms-trackers-integration==0.7.0
 raven==6.10.0
 social-auth-app-django==5.4.0