Consider exposing the Generation of an AttestationReport #389

The crate already has the logic to derive a Generation enum from an attestation report (e.g. in the impl Encoder<()> for AttestationReport implementation).

The generation is necessary in order to e.g. encode/decode the TcbVersion. However, the generation is not exposed, so users must duplicate the generation detection logic from the crate.

Would be nice to have a field or a method on AttestationReport that clients could use to retrieve the generation of the plaform.