metafields in webhook filtering includeFields

 shopify: {
      shopifyFilter: "variants.metafields.$app.my-app.key1:* OR variants.metafields.$app.my-app.key2:*",
      includeFields: [
        "id",
        "body", 
        "category",
... more product fields
        "variants.title",
... more variant fields
        "variants.metafields.$app.my-app.key1",
        "variants.metafields.$app.my-app.key2",
... more metafields
      ]
    }