curl --request PATCH \
  --url https://api.deck.co/v2/credentials/{credential_id} \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "auth_credentials": {
    "username": "<string>",
    "password": "<string>",
    "source_fields": {}
  },
  "external_id": "<string>"
}
'

{
  "id": "<string>",
  "object": "<string>",
  "status": "<string>",
  "source_id": "<string>",
  "auth_method": "<string>",
  "auth_credentials": {
    "username": "<string>"
  },
  "external_id": "<string>",
  "created_at": "2023-11-07T05:31:56Z",
  "updated_at": "2023-11-07T05:31:56Z",
  "request_id": "<string>"
}