d/control: add missing dependency for `sort`

The new implementation of `sort` backported from upstream adds a
dependency on the `rayon` crate. This commit adds the corresponding
Debian package as a build-dependency.

Signed-off-by: Arnaud Ferraris <arnaud.ferraris@collabora.com>

debian/control

@@ -26,7 +26,7 @@ Build-Depends: debhelper (>= 12),
  librust-rand-pcg-dev, librust-thiserror-dev, librust-lazy-static-dev,
  librust-byteorder-dev, librust-hostname-dev (>= 0.3.1), librust-cpp-build-dev,
  librust-fnv-dev, librust-wild-dev, librust-cpp-dev, librust-thread-local-dev,
- librust-backtrace-sys-dev, python3-sphinx, help2man
+ librust-backtrace-sys-dev, librust-rayon-dev, python3-sphinx, help2man
 Maintainer: Debian Rust Maintainers <pkg-rust-maintainers@alioth-lists.debian.net>
 Uploaders:
  Sylvestre Ledru <sylvestre@debian.org>