fix build with pipewire-jack

[Be-ing]

RustAudio/rust-jack#154

[Boddlnagg]

Thank you! The update of the jack-sys version included in #98 should make this PR unnecessary, but I'll leave it open until that PR is merged.

[Boddlnagg]

If you say that jack-sys version 0.2.3 is required, would #98 be sufficient? It upgrades to version ~0.2.1, but that would be semver-compatible with version 0.2.3, if I'm not mistaken. So you could get midir to use 0.2.3 by requiring 0.2.3 in your downstream crate.

I will still leave this issue open until the required version of jack-sys is 0.2.3 or later.

[Be-ing]

How about simply using jack-sys = "0.2" without specifying the patch version?

[Boddlnagg]

Yep, that's a good idea :-)