curl --request PUT \
  --url https://app.dynamicauth.com/api/v0/custom/fields/{customFieldId} \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{
  "name": "An example name",
  "enabled": true,
  "required": true,
  "fieldType": "text",
  "validationRules": {
    "unique": true,
    "regex": "^0x",
    "validOptions": [
      {
        "label": "small"
      },
      {
        "label": "medium"
      },
      {
        "label": "large"
      }
    ],
    "checkboxText": "Agree to the terms and conditions"
  },
  "position": 123
}'

{
  "id": "95b11417-f18f-457f-8804-68e361f9164f",
  "key": "An example name",
  "name": "An example name",
  "enabled": true,
  "required": true,
  "fieldType": "text",
  "validationRules": {
    "unique": true,
    "regex": "^0x",
    "validOptions": [
      {
        "label": "small"
      },
      {
        "label": "medium"
      },
      {
        "label": "large"
      }
    ],
    "checkboxText": "Agree to the terms and conditions"
  },
  "position": 123
}