* [Make `replacement` a label of the replacement
  encoding.](https://github.com/whatwg/encoding/issues/70) (Spec change.)
* Remove `Encoding::for_name()`. (`Encoding::for_label(foo).unwrap()` is
  now close enough after the above label change.)
* Remove the `parallel-utf8` cargo feature.
* Add optional Serde support for `&'static Encoding`.
* Performance tweaks for ASCII handling.
* Performance tweaks for UTF-8 validation.
* SIMD support on aarch64.