Soundness issue in raw-cpuid

VendorInfo::as_string(), SoCVendorBrand::as_string(), and ExtendedFunctionInfo::processor_brand_string() construct byte slices using std::slice::from_raw_parts(), with data coming from #[repr(Rust)] structs. This is always undefined behavior.
This flaw has been fixed in v9.0.0, by making the relevant structs #[repr©].