spotifyaudiosrc: Update to librespot 0.4

CC @gdesmott

Thanks, I just tested it and it works fine!

approved this merge request

merged

mentioned in issue #204 (closed)

@gdesmott I wonder why they did a newer release but there are so many outdated dependencies still.

Good point, I reported it.

If you don't mind switching the dependency to unreleased code, we could use their new-api branch which has newer deps. That would also unblock my spotify lyrics element.

That means we couldn't do releases :)