curl --request POST \
  --url https://api.oquiz.net/files/upload \
  --header 'Authorization: <api-key>' \
  --header 'Content-Type: multipart/form-data' \
  --form 'entityName=<unknown>' \
  --form 'entityId=<string>' \
  --form file='@example-file'

{
  "colors": [
    "<string>"
  ],
  "file": {
    "src": "<string>",
    "color": "<string>",
    "duration": 123
  }
}