v0.5.0

[v0.5.0] - 2023-08-02

• Improve custom error handling: custom errors now require Debug + Display on no_std or Error on std.
  Error::custom() now accepts anything implementing these traits rather than depending on Into<Error>
  (#13).
• Enable using #[codec(skip)] or #[encode_as_type(skip)] to ignore fields when using the EncodeAsType macro.
  Skipping isn't generally necessary, but can be useful in edge cases (such as allowing a multi-field struct to be
  encoded to a number if all but one numeric field is skipped) (#16).