Re-release of v0.4.3 since PR#34 was not included.
This release includes initial support for a VM-specific additional certificate that is possible to add with SEV-SNP host patch series v7's KVM_SEV_SNP_SET_CERTS command. The GUID here is what we chose to identify the GCE firmware endorsement document. More details about the endorsement document are coming later, perhaps in a different repository.