0.78.6
(fix): Support null in an enum (functionality is delegated to nullable<>).
0.78.5
(fix): Correct nullable<> wrapping of nullable schemas referenced via $ref.
0.78.4
(fix): Collapse any combination of optional and nullable to optional<nullable<T>>.
0.78.3
(chore): Support IR v59 in the Rust SDK generator.
