Update a coupon

curl --request PUT \
  --url https://api.cloud.flexprice.io/v1/coupons/{id} \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: <api-key>' \
  --data '{
  "metadata": {},
  "name": "<string>"
}'

{
  "amount_off": 123,
  "cadence": "once",
  "created_at": "<string>",
  "created_by": "<string>",
  "currency": "<string>",
  "duration_in_periods": 123,
  "environment_id": "<string>",
  "id": "<string>",
  "max_redemptions": 123,
  "metadata": {},
  "name": "<string>",
  "percentage_off": 123,
  "redeem_after": "<string>",
  "redeem_before": "<string>",
  "rules": {},
  "status": "published",
  "tenant_id": "<string>",
  "total_redemptions": 123,
  "type": "fixed",
  "updated_at": "<string>",
  "updated_by": "<string>"
}