Update Cargo.lock

This is not the result of a pure cargo update, as that would add
a new vorbis-sys version, conflicting with itself.

Instead, we ran the following:
cargo update -p alto -p bitflags -p bytes -p cc -p conv -p custom_derive -p futures -p iovec -p libc -p libloading -p log -p pkg-config -p syn -p tokio-io -p unicode-xid -p parking_lot_core -p proc-macro2 -p quote -p rental -p rental-impl -p syn -p unicode-xid -p winapi:0.3.6 -p rand:0.3.16 -p smallvec:1.1.0

It all still compiles on our MSRV 1.36.0 which is good.

Author: est31