libspotify 12.1.51.1

# libspotify This is a mere ruby gem that bundles the libspotify binaries for ease of installation. Please see [the official libspotify documentation at https://developer.spotify.com/technologies/libspotify/ for more information](https://developer.spotify.com/technologies/libspotify/). # Version policy Given `12.1.51.0`, the `12.1.51` is the libspotify version, and the last `0` means it’s the first version released of the libspotify gem for this libspotify version.