Driver: Replace xsalsa20poly1305 with crypto_secretbox (#198)

As of v0.9.1, `xsalsa20poly1305` has been deprecated. This is a mostly seamless replacement, as it appears to be the same crate authors / code / etc.

Co-authored-by: Kyle Simpson <kyleandrew.simpson@gmail.com>

src/driver/tasks/error.rs

@@ -1,9 +1,9 @@
 use super::message::*;
 use crate::ws::Error as WsError;
 use audiopus::Error as OpusError;
+use crypto_secretbox::aead::Error as CryptoError;
 use flume::SendError;
 use std::io::{Error as IoError, ErrorKind as IoErrorKind};
-use xsalsa20poly1305::aead::Error as CryptoError;
 
 #[derive(Debug)]
 pub enum Recipient {