curl --request PUT \
  --url https://app.herondata.io/api/end_users/{end_user_heron_id}/entities/values/bulk \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: <api-key>' \
  --data '
{
  "values": [
    {
      "attribute_name": "<string>",
      "entity_name": "<string>",
      "value": "<unknown>"
    }
  ]
}
'

[
  {
    "attribute_name": "<string>",
    "entity_name": "<string>",
    "success": true,
    "error": null
  }
]