curl --request POST \
  --url https://integration.getmateo.com/api/v1/custom_field \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{
  "id": "random uuid",
  "created_at": "now()",
  "updated_at": "now()",
  "organisation_id": "random uuid",
  "name": "<string>",
  "description": "<string>",
  "type": "string",
  "key": "<string>",
  "entity": "contact"
}'

{
  "id": "random uuid",
  "created_at": "now()",
  "updated_at": "now()",
  "organisation_id": "random uuid",
  "name": "<string>",
  "description": "<string>",
  "type": "string",
  "key": "<string>",
  "entity": "contact"
}