Changelog for ppad-sha256-0.2.0

# Changelog - 0.2.0 (2024-10-07) * 'hmac' and 'hmac_lazy' now hash long keys before computing a HMAC, instead of throwing an error, matching RFC 2104's suggested behaviour. - 0.1.0 (2024-09-14) * Initial release, supporting SHA256 and HMAC-SHA256 on strict and lazy bytestrings.