curl --request POST \
  --url https://api.opereit.com/v1/invoice-audits \
  --header 'Authorization: Basic <encoded-value>' \
  --header 'Content-Type: multipart/form-data' \
  --form file='@example-file' \
  --form 'contract_id=<string>'

{
  "audit": {
    "id": "<string>",
    "contract_id": "<string>",
    "status": "PENDING",
    "created_at": "2023-11-07T05:31:56Z",
    "carrier_name": "<string>",
    "status_reason": "<string>",
    "total_line_items": 123,
    "completed_at": "2023-11-07T05:31:56Z",
    "file": {
      "id": "<string>",
      "file_url": "<string>",
      "file_name": "<string>",
      "original_file_name": "<string>",
      "created_at": "2023-11-07T05:31:56Z",
      "file_size_bytes": 123,
      "invoice_number": "<string>",
      "invoice_date": "2023-12-25",
      "account_number": "<string>",
      "billing_period_start": "2023-12-25",
      "billing_period_end": "2023-12-25",
      "currency": "<string>"
    }
  }
}