"basic" example crashes with PulseAudio on LInux

[frazar]

Running the "basic" example produces a crash on my machine with the following output.

$ cargo run --example basic
    Finished dev [unoptimized + debuginfo] target(s) in 0.23 secs
     Running `target/debug/examples/basic`
thread 'main' panicked at 'sample rate could not be set: "Invalid argument"', libcore/result.rs:945:5
note: Run with `RUST_BACKTRACE=1` for a backtrace.

I think this is related to an issue in cpal, where the maximum sample rate reported by ALSA is "garbage" (4294967295) when using PulseAudio.

The issue has has been solved in cpal >= 0.8 by using a better default, so updating the dependency version might be sufficient.