Support verified for all new Swifts.

Buildmetadata is ignored for Equatable. Previously we only ignored it for Comparable. Revisiting the spec indicates this was incorrect. Major version bump due to this being a behavioral change.

This impacts how eg. dictionaries and sets will behave too since Hashable needs to behave the same as ==. See the README for details.

Decoding method can be defined as part of the decoder’s userInfo property.