"unpack" fails when used with "--cache_dir" option

[mite-user]

unpack.rs tries to write a bunch of .xwin-cache/unpack/{}/tree.txt relative to the current folder.
If the current folder doesn't contain .xwin-cache with the same directory structure, the program fails to unpack.

How to reproduce on Linux.

Create 2 empty folders and cd into one of them.

mkdir "${HOME}/cd" "${HOME}/dest"
cd "${HOME}/cd"

Run xwin unpack with --cache-dir pointing to another empty folder.

RUST_BACKTRACE=1 xwin --accept-license="yes" --cache-dir="${HOME}/dest" unpack

It fails after each unpack.

thread '<unnamed>' panicked at 'called `Result::unwrap()` on an `Err` value: Os { code: 2, kind: NotFound, message: "No such file or directory" }', /home/user/.cargo/registry/src/github.com-1ecc6299db9ec823/xwin-0.1.2/src/unpack.rs:577:6