draft-connolly-cfrg-xwing-kem-01

What's Changed

• Store copy of X25519 public key in X-Wing decapsulation key by @bwesterb in #10

Full Changelog: https://github.com/dconnolly/draft-connolly-cfrg-xwing-kem/commits/draft-connolly-cfrg-xwing-kem-01