chore(docs): Updated API Reference (v2) (#9437)

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/AdminApplicationMethod.yaml

@@ -0,0 +1,79 @@
+type: object
+description: The application method's details.
+x-schemaName: AdminApplicationMethod
+required:
+  - id
+properties:
+  promotion:
+    $ref: ./AdminPromotion.yaml
+  target_rules:
+    type: array
+    description: The application method's target rules.
+    items:
+      $ref: ./AdminPromotionRule.yaml
+  buy_rules:
+    type: array
+    description: The application method's buy rules.
+    items:
+      $ref: ./AdminPromotionRule.yaml
+  id:
+    type: string
+    title: id
+    description: The application method's ID.
+  type:
+    type: string
+    description: >-
+      The application method's type. If it's `fixed`, the promotion discounts a
+      fixed amount. If it's `percentage`, the promotion discounts a percentage.
+    enum:
+      - fixed
+      - percentage
+  target_type:
+    type: string
+    description: >-
+      Which item does the promotion apply to. `items` mean the promotion applies
+      to the cart's items; `shipping_methods` means the promotion applies to the
+      cart's shipping methods; `order` means the promotion applies on the entire
+      order.
+    enum:
+      - items
+      - shipping_methods
+      - order
+  allocation:
+    type: string
+    description: >-
+      How is the promotion amount discounted. `each` means the discounted amount
+      is applied on each applicable item; `across` means the discounted amount
+      is split accross the applicable items.
+    enum:
+      - each
+      - across
+  value:
+    type: number
+    title: value
+    description: The amount to be discounted.
+  currency_code:
+    type: string
+    title: currency_code
+    description: The application method's currency code.
+    example: usd
+  max_quantity:
+    type: number
+    title: max_quantity
+    description: >-
+      The max quantity allowed in the cart for the associated promotion to be
+      applied.
+  buy_rules_min_quantity:
+    type: number
+    title: buy_rules_min_quantity
+    description: >-
+      The minimum quantity required for a `buyget` promotion to be applied. For
+      example, if the promotion is a "Buy 2 shirts get 1 free", the value of
+      this attribute is `2`.
+  apply_to_quantity:
+    type: number
+    title: apply_to_quantity
+    description: >-
+      The quantity that results from matching the `buyget` promotion's
+      condition. For example, if the promotion is a "Buy 2 shirts get 1 free",
+      the value of this attribute is `1`.