Changelog for musig2-0.1.1

# Changelog ## 0.1.1 (2025-12-22) * Bump `ppad-secp256k1` to 0.5.0. More efficient and faster EC operations. ## 0.1.0 (2025-09-20) * Initial release, full BIP-0327 support except [Deterministic and Stateless Signing for a Single Signer](https://github.com/bitcoin/bips/blob/master/bip-0327.mediawiki#user-content-Deterministic_and_Stateless_Signing_for_a_Single_Signer)