Pass client logger to anacrolix/go-libutp sockets (#722)
* Update anacrolix/go-libutp (v1.1.0 -> v1.2.0)
* Pass client logger to anacrolix/go-libutp
* Pass logger instead of option
The project now compiles properly when CGO is not enabled.
Additionally, the new argument (now log.Logger instead of
utp.NewSocketOpt) is now required. The tests have been updated to match
this change, and now pass logger.Default to NewUtpSocket.