[Virtio-fs] [virtiofsd] MR opened: Bump vhost-user-backend and virtio-queue dependencies

[virtiofs-bot at sinrega.org]

Updating dependencies to:
- virtio-queue 0.5.0
- vhost-user-backend 0.6.0

This latest virtio-queue version introduces a few breaking changes,
which is why this patch slightly updates the code.

The latest vhost-user-backend version relies on the same virtio-queue
version, but it also contains a fix for proper vring initialization so
that booting a VM with OVMF firmware works as expected.

Signed-off-by: Sebastien Boeuf <sebastien.boeuf at intel.com>
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https://gitlab.com/virtio-fs/virtiofsd/-/merge_requests/129