Cert-cvc 1.2.8 released

This release of the library for CV certificates, as used in EU EAC
ePassport PKIs, adds support for HSMs for ECC signatures. There was wan
issue in 1.2.7 that made the signatures not work when using an pkcs#11
signature provider.

This in turn is because the EAC specification decided not to use the
standard X9.62 signature format for ECC signatures.