Merge pull request #124 from knikolla/2025_09_outage

Add 2025-09 outage

Author: knikolla

src/openstack_billing_db/billing.py

@@ -24,6 +24,7 @@
     "2025-05": [("2025-05-13 12:00:00", "2025-05-13 21:00:00")],
     "2025-06": [("2025-06-02 19:00:00", "2025-06-04 21:00:00")],
     "2025-08": [("2025-08-12 12:00:00", "2025-08-12 21:00:00")],
+    "2025-09": [("2025-09-09 12:00:00", "2025-09-09 21:00:00")],
 }