Update audio file with upload

Update the content of an existing audio file. The content will be processed
asynchronously. The status property of the updated audio file will transition
through the following stages:

• pending-conversion
• processing
• Finally, it will be either ready or error

The supported formats are audio/flac, audio/mpeg, audio/mp4, audio/ogg,
audio/wav.

You can use webhooks to receive updates on the status.