Add update for location in order to support patch (#25192)

Author: chchen3

specification/reservations/resource-manager/Microsoft.Capacity/stable/2022-11-01/reservations.json

@@ -3013,7 +3013,8 @@
           "description": "The Azure region where the reserved resource lives.",
           "x-ms-mutability": [
             "create",
-            "read"
+            "read",
+            "update"
           ]
         },
         "properties": {