Sort files when creating the tar

This makes the binary more reproducible by ensuring the files are added in a stable order.

cc https://github.com/NixOS/nixpkgs/pull/60022

re:

• https://r13y.com/
• https://r13y.com/diff/bfb79a5970edba7263632a5fdffa7972f95ff36ba858911bc1ebf7df72fa8bbd-854a9c2d3f93baa07b5db3ab9a104b626193ded2d14b31adb0d1d0a17e3a6252.html