curl --request PUT \
  --url https://{tenant}.stamp.eu/rest/datev/employee-mappings \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "mappings": [
    {
      "employee_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
      "datev_mitarbeiter_nummer": "<string>"
    }
  ]
}
'

{
  "data": [
    {
      "id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
      "employee_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
      "datev_mitarbeiter_nummer": "<string>",
      "employee": {
        "id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
        "name": "<string>",
        "surname": "<string>"
      }
    }
  ]
}