FilesInfo's JsonFormat stackoverflows

[Dale Wijnand]

util/internal/util-cache/src/main/scala/sbt/internal/util/FileInfo.scala

Line 172 in 613bf8b

 implicit def format[F <: FileInfo]: JsonFormat[FilesInfo[F]] = implicitly 

I'm pretty sure

implicit def format[F <: FileInfo]: JsonFormat[FilesInfo[F]] = implicitly

is never going to work.