chore(docs): Updated API Reference (v2) (#8609)

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

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

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

@@ -0,0 +1,37 @@
+type: object
+description: SUMMARY
+x-schemaName: AdminPostExchangesAddItemsReqSchema
+properties:
+  items:
+    type: array
+    description: The exchange's items.
+    items:
+      type: object
+      description: The item's items.
+      required:
+        - variant_id
+        - quantity
+      properties:
+        variant_id:
+          type: string
+          title: variant_id
+          description: The item's variant id.
+        quantity:
+          type: number
+          title: quantity
+          description: The item's quantity.
+        unit_price:
+          type: number
+          title: unit_price
+          description: The item's unit price.
+        internal_note:
+          type: string
+          title: internal_note
+          description: The item's internal note.
+        allow_backorder:
+          type: boolean
+          title: allow_backorder
+          description: The item's allow backorder.
+        metadata:
+          type: object
+          description: The item's metadata.