The tar command in package-cli produces a non-reproducible archive
because file ordering and timestamps vary between builds. This causes
bit-for-bit differences when rebuilding k3s from the same source,
which breaks reproducible build systems such as Nix.
Sort the archive entries by name and clamp modification times to the
Unix epoch so the tarball content is deterministic regardless of
filesystem ordering or build time.
Ref: NixOS/nixpkgs#430225
Ref: NixOS/nixpkgs#502374
Signed-off-by: Jon Hermansen <jon@jh86.org>