PROMO-1050 Add shipping discount action

Author: bc-luke

Diff for: reference/promotions.v3.yml

@@ -34,7 +34,7 @@ paths:
     get:
       tags:
         - Promotions (Bulk)
-      summary: Get All Promotions 
+      summary: Get All Promotions
       description: |-
         Returns a list of *promotions*.
 
@@ -120,7 +120,7 @@ paths:
     get:
       tags:
         - Promotions (Single)
-      summary: Get Promotion 
+      summary: Get Promotion
       description: |-
         Returns a single *promotion*.
 
@@ -170,7 +170,7 @@ paths:
     delete:
       tags:
         - Promotions (Single)
-      summary: Delete Promotion 
+      summary: Delete Promotion
       description: |-
         Deletes a promotion.
 
@@ -189,7 +189,7 @@ paths:
     get:
       tags:
         - Coupon Codes (Bulk)
-      summary: Get Coupon Codes 
+      summary: Get Coupon Codes
       description: |-
         Get codes for a particular promotion.
 
@@ -204,7 +204,7 @@ paths:
     post:
       tags:
         - Coupon Codes (Single)
-      summary: Create A Coupon Code 
+      summary: Create A Coupon Code
       description: |-
         Create a new code for the promotion.
 
@@ -242,7 +242,7 @@ paths:
     delete:
       tags:
         - Coupon Codes (Bulk)
-      summary: Delete Multiple Coupon Codes 
+      summary: Delete Multiple Coupon Codes
       description: |-
         Deletes multiple coupon codes relating to the given promotion. Currently, batches are limited to 50 coupon codes.
 
@@ -819,6 +819,33 @@ components:
                     minimum: 1
           required:
             - zone_ids
+    ShippingDiscountAction:
+      title: Shipping Discount Action
+      type: object
+      description: |-
+        **Shipping Discount Action**
+        Discounts shipping, optionally restricted to specific shipping methods.
+      properties:
+        shipping_discount:
+          type: object
+          properties:
+            discount:
+              $ref: '#/components/schemas/Discount'
+            method_ids:
+              description: ''
+              oneOf:
+                - type: string
+                  enum:
+                    - '*'
+                  description: All configured shipping methods.
+                - type: array
+                  uniqueItems: true
+                  description: List of shipping method IDs to which the shipping discount can apply.
+                  items:
+                    type: integer
+                    minimum: 1
+          required:
+            - method_ids
     Discount:
       title: Discount
       description: '**Discount**'
@@ -928,9 +955,9 @@ components:
           type: array
           description: Specifies where the notification message will be displayed.
           example:
-            - HOME_PAGE 
-            - PRODUCT_PAGE 
-            - CART_PAGE 
+            - HOME_PAGE
+            - PRODUCT_PAGE
+            - CART_PAGE
             - CHECKOUT_PAGE
           items:
               type: string
@@ -1338,7 +1365,7 @@ components:
               success: 0
               failed: 0
         422 - Error Deleting:
-          example: 
+          example:
             errors:
               - status: 422
                 title: Errors occurred in bulk delete action.