chore(docs): Updated API Reference (automated) (#13794)

Automated changes by [create-pull-request](https://github.com/peter-evans/create-pull-request) GitHub action

Co-authored-by: Oli Juhl <59018053+olivermrbl@users.noreply.github.com>
Co-authored-by: Shahed Nasser <27354907+shahednasser@users.noreply.github.com>

www/apps/api-reference/specs/admin/components/schemas/AdminCampaign.yaml

@@ -51,6 +51,7 @@ properties:
       - currency_code
       - limit
       - used
+      - attribute
     properties:
       id:
         type: string
@@ -82,6 +83,13 @@ properties:
           property holds the total amount discounted so far. If the limit is
           `usage`, it holds the number of times the campaign's promotions have
           been used so far.
+      attribute:
+        type: string
+        title: attribute
+        description: The cart attribute to limit the budget by.
+        externalDocs:
+          url: >-
+            https://docs.medusajs.com/resources/commerce-modules/promotion/campaign#attribute-based-budgets
   created_at:
     type: string
     format: date-time