The unstable branch of `yabar` received some minor useful changes:
- Fixed missprint (f1b1eff481)
- Update information on Debian installation (ce20fe75f7)
- Add indicator to show current indicator using `libxkbcommon` (5aa1fb5eb5)
The last change requires a `libxkbcommon` as additional build input.
Furthermore I thought that it might be better to add the dependencies of
unstable (namely `playerctl` and `libxkbcommon`) to the `unstable.nix`
to reduce the closure size of the stable build.
