Create or update a promotion

curl --request POST \
     --url https://app.amberflo.io/payments/pricing/amberflo/account-pricing/promotions/generic_item_promotion \
     --header 'accept: application/json' \
     --header 'content-type: application/json' \
     --data '{
     "id": "",
     "type": "generic_item_promotion",
     "promotionName": "",
     "condition": {
     "type": "after_item_price_threshold"
     },
     "promotionModel": {
     "type": "absolute",
     "measure": {
     "type": "per_batch"
     }
     }
     }'