Make sure TASTy reader is good to go for 3.1.0 / 2.13.7 releases

[SethTisue]

@bishabosha as per https://contributors.scala-lang.org/t/scala-2-13-7-release-planning/5221/3 , we'd like to release Scala 2.13.7 around November 1, though not before 3.1.0 comes out. Can you take care of any needed changes?

[bishabosha]

Hey, I'm just back from vacation, I will see to this

[SethTisue]

@bishabosha just checking in about this? (now that Scala 3.1 has shipped, it would be really nice for 2.13.7 not to slip)

[bishabosha]

I have started on a branch to integrate the changes for 3.1.0

[SethTisue]

in case anyone out there is trying to use the 2.13.6 tasty reader with 3.1 and failing, note that the error message (according to @bplommer) is:

[error] error while loading package, class file '/Users/benplom/Library/Caches/Coursier/v1/https/repo1.maven.org/maven2/co/fs2/fs2-core_3/3.2.0/fs2-core_3-3.2.0.jar(fs2/package.class)' is broken
[error] (class scala.tools.tasty.UnpickleException/TASTy signature has wrong version.
[error]  expected: {majorVersion: 28, minorVersion: 0}
[error]  found   : {majorVersion: 28, minorVersion: 1}
[error] 
[error] This TASTy file was produced by a more recent, forwards incompatible release.
[error] To read this TASTy file, please upgrade your tooling.
[error] The TASTy file was produced by Scala 3.1.0.)

adding this here to aid googleability

[SethTisue]

fixed by scala/scala#9791