message: fix metafields type and add quantity
diff: @@ -66,12 +66,13 @@ interface Shop {
  * only public listed metafields are available
  * https://shopify.dev/tutorials/retrieve-metafields-with-storefront-api#expose-metafields-to-the-storefront-api
  */
  - metafields: {[key: string]: string};
  + metafields: Metafield[];
  }
  interface LineItem {
  /** product being purchased */
  product: Product;
  + quantity: number;
  }
  interface Product {
  @@ -85,7 +86,7 @@ interface Product {
  * only public listed metafields are available
  * https://shopify.dev/tutorials/retrieve-metafields-with-storefront-api#expose-metafields-to-the-storefront-api
  */
  - metafields: {[key: string]: string};
  + metafields: Metafield[];
  }
  interface Variant {
  @@ -96,5 +97,12 @@ interface Variant {
  * only public listed metafields are available
  * https://shopify.dev/tutorials/retrieve-metafields-with-storefront-api#expose-metafields-to-the-storefront-api
  */
  - metafields: {[key: string]: string};
  + metafields: Metafield[];
  +}
  +
  +interface Metafield {
  + key: string;
  + namespace: string;
  + value: string | number;
  + valueType: 'integer' | 'string' | 'json_string';
  }
  