Changelog of @hackage/flat 0.3

Significant and compatibility-breaking changes.

Version 0.3: - Removed 'flatStrict' and 'unflatStrict' (use 'flat' and 'unflat' instead that also encode/decode strictly) - unflatWith now takes a decoder for the unpadded value (previously it expected a padded decoder) and decodes the padded value - Added some decoding primitives - Added Data.ByteString.Convert