frost-core v2.2.0

Security Fixes

• Added validation for the min_signers parameter in the
  frost_core::keys::refresh functions. It was not clear that it is not
  possible to change min_signers with the refresh procedure. Using a smaller
  value would not decrease the threshold, and attempts to sign using a smaller
  threshold would fail. Additionally, after refreshing the shares with a smaller
  threshold, it would still be possible to sign with the original threshold;
  however, this could cause a security loss to the participant's shares. We have
  not determined the exact security implications of doing so and judged simpler
  to just validate min_signers. If for some reason you have done a refresh
  share procedure with a smaller min_signers we strongly recommend migrating
  to a new key. Thank you BlockSec for reporting the
  finding.

Other Changes

• MSRV has been bumped to Rust 1.81, making all crates no-std (except
  frost-ed448).
• Added DKG refresh functions to the crate-specific refresh modules.
• Added VerifiableSecretSharingCommitment::{serialize,deserialize}_whole()
  methods.
• Added Ciphersuite::post_generate() method to allow more ciphersuite
  customization.

Acknowledgments

A big thank you to all the contributors who made this release possible: @VolodymyrB, @StackOverflowExcept1on, @crStiv, @azuchi, @conradoplg and @natalieesk