Strange error in BooPickle perf tests

[fomkin]

[error] D:\work\boopickle\perftests\shared\src\main\scala\boopickle\perftests\TestData.scala:8: type mismatch;
[error]  found   : Some[A]
[error]  required: Option[pushka.HasDefault.Default[String]]
[error] @pushka case class Book(id: String, name: String, author: String, publicationYear: Int)
[error]  ^

[fomkin]

Reported by @ochrons