curl --request POST \
  --url https://api.lemlist.com/api/leads/audio \
  --header 'Authorization: Basic <encoded-value>' \
  --header 'Content-Type: multipart/form-data' \
  --form file=@example-file

{
  "ok": true,
  "status": {
    "url": "https://lemlist-dev.s3.eu-west-1.amazonaws.com/fil_bECTszeFQMneA43D2.m4a",
    "teamId": "tea_KWvTf2CypcBqG4QG2",
    "campaignId": "cam_B3MJETF3YxvGaR4dC",
    "leadId": "lea_CgfmTDCPC43gwPgYk",
    "fileName": "file2"
  }
}