[ANNOUNCE] cloud-hypervisor-38.0-spectrum0

I've updated Spectrum's Cloud Hypervisor patches (which add virtio-gpu support) to support the recently released Cloud Hypervisor 38.0. Also new in this release: • Support for adding GPU devices using Cloud Hypervisor's optional D-Bus API. • ch-remote now has an add-gpu subcommand. • GPU support in the API is now documented in the OpenAPI definition. More information is available at <https://spectrum-os.org/software/cloud-hypervisor/>. (I'm still not sure what the right place to announce these updates is…)