Changelog for ppad-bip32-0.2.0

# Changelog - 0.2.0 (2025-06-21) * The 'xprv' and 'tprv' functions are now total, returning 'Nothing' when derivation is impossible. * The 'XPrv', 'XPub', and 'X' constructors are no longer exported. Instead, use the 'x{prv,pub}_key' and 'x{prv,pub}_cod' functions to work with their contents. - 0.1.1 (2025-02-23) * Haddock improvements and examples. - 0.1.0 (2025-02-22) * Initial release, supporting basic HD wallet functionality.