wireguard: selftests: bump package deps

Use newer, more reliable package dependencies. These should hopefully
reduce flakes. However, we keep the old iputils package, as it
accumulated bugs after resulting in flakes on slow machines.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>