c733f0bf8a switched JACK to using overlay-style
mkDerivation, but forgot to change a reference to `version` to `finalAttrs.version`.
This wasn't caught at eval time because `with lib` was used, making the
source derivation try to fetch (at the time of writing) tag "23.05pre-git",
which obviously doesn't exist :D
Thanks to V for catching this [0].
[0]: https://github.com/NixOS/nixpkgs/pull/216096#issuecomment-1437763295