curl --request POST \
  --url https://api.valyx.com/invoice/attachment/upload \
  --header 'Content-Type: application/json' \
  --header 'X-Valyx-Attachment-Upload-Signature: <x-valyx-attachment-upload-signature>' \
  --data '
{
  "invoiceNumber": "<string>",
  "attachmentUrl": "<string>",
  "purpose": "INVOICE_FOR_BUYER"
}
'

{
  "error": "<string>",
  "message": "<string>",
  "data": {
    "invoiceId": "<string>",
    "invoiceNumber": "<string>",
    "customerName": "<string>",
    "buyerId": "<string>",
    "attachments": [
      {
        "filename": "<string>",
        "purpose": "<string>",
        "createdAt": "<string>"
      }
    ]
  }
}