Get Upload Url

curl --request POST \
  --url https://api.example.com/api/v1/datasets/{dataset_id}/audio/upload-url \
  --header 'Content-Type: application/json' \
  --header 'X-API-Key: <api-key>' \
  --data '
{
  "filename": "<string>",
  "content_type": "<string>",
  "file_size": 123
}
'

{
  "upload_url": "<string>",
  "fields": {},
  "key": "<string>",
  "expires_in": 123,
  "audio_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a"
}