curl --request POST \
  --url http://localhost:8080/users/{user_id}/dependants/bulk \
  --header 'Content-Type: application/json' \
  --data '
{
  "dependants": [
    {
      "date_of_birth": "2000-01-15",
      "first_name": "<string>",
      "last_name": "<string>"
    }
  ]
}
'

{
  "data": [
    {
      "created_at": "<string>",
      "date_of_birth": "2000-01-15",
      "first_name": "<string>",
      "id": "<string>",
      "last_modified_at": "<string>",
      "last_name": "<string>",
      "previous_version_id": "<string>",
      "primary_user_id": "012345678901"
    }
  ]
}