curl \
 -X PUT http://test.api.fygi.store/external/api/discount-codes/{discountCodeExternalId}/campaign \
 -H "authorization: $API_KEY" \
 -H "Content-Type: application/json" \
 -d '{"externalIds":["string"]}'

curl \
 -X PUT http://test.api.fygi.store/external/api/discount-codes/{discountCodeExternalId}/campaign \
 -H "authorization: $API_KEY" \
 -H "Content-Type: text/json"

curl \
 -X PUT http://test.api.fygi.store/external/api/discount-codes/{discountCodeExternalId}/campaign \
 -H "authorization: $API_KEY" \
 -H "Content-Type: application/*+json"

{
  "externalIds": [
    "string"
  ]
}

{
  "externalIds": [
    "string"
  ]
}

{
  "externalIds": [
    "string"
  ]
}