[Rust] Firecracker 1.5 crate updates

[David Michael]

Hi,

The firecracker-1.5 update has a few new crate dependencies.  These
are compatible minor version updates:

clap-4.4.6 (from 4.4.4)
regex-1.9.6 (from 1.9.5)

A new crate is added:

clap-num-1.0.2 https://bugzilla.redhat.com/2243746

And there are three updates with incompatible API versions:

kvm-ioctls-0.15.0
nix-0.27.1
userfaultfd-0.7.0

I will include userfaultfd as part of the Firecracker update since
it's the only user of that crate.

The nix crate has many users, and it seems to get compatibility
packages for API updates.  Can that be done for 0.26, or should I try
to downgrade the crate with a patch?

It seems like krun and sev are the only other users of kvm-ioctls, and
they have open-ended version dependencies (>=0.12.0).  Is it
straightforward to update kvm-ioctls then?  I would rather not try to
downgrade this via patching since features in the release changelog
depend on the new version.

Let me know how it is preferred to handle these.  You can add me as a
co-maintainer for any of them if you want me to do the updates.

Thanks.

David