Upgrade version of scala in build.sbt to 2.12.10

[metterklume]

On Mac Os running 'sbt test' gave me a
[error] java.io.IOError: java.lang.RuntimeException: /packages cannot be represented as URI

Suggested Fix
In build.sbt:

scalaVersion := "2.12.8"
--> scalaVersion := "2.12.10"

System details

sbt --version
sbt version in this project: 1.3.8
sbt script version: 1.3.8

java --version
  java 12 2019-03-19
  Java(TM) SE Runtime Environment (build 12+33)
  Java HotSpot(TM) 64-Bit Server VM (build 12+33, mixed mode, sharing)

[anne-turpaud]

I wanted to give this issue a shoutout, because I had the exact same issue and the suggested fix worked wonders for me. Thanks !

[ErikSchierboom]

@metterklume @anne-turpaud Would one of you be interested in doing a PR to update the exercises to the suggested sbt version?

[anne-turpaud]

I can't promise I'll do it extremely quickly because I've just discovered these Scala exercices, but yes, I can have a look into it.

[ErikSchierboom]

@anne-turpaud No rush! Take your time :)

[LarsWestergren]

Does this only refer to the exercises themselves? If so, scala version in all tests seem to have been updated in
commit 582a3f5
to 2.13.6

If so, this can be closed. There is however in this project itself, a reference to scala 2.12.8:
./project/Build.scala

Should this be updated too?

[LarsWestergren]

These files look unused since they are so out of date?
https://github.com/exercism/scala/tree/main/project

I can update them if required, otherwise I will add PR to delete them, then this issue can be closed since the scala version for exercises have been updated to 2.13.6 (and a Scala 3 update is on the way).

[ErikSchierboom]

I think those files are no longer used. They used to be used in CI, but that now runs https://github.com/exercism/scala/blob/main/bin/test in which I don't see any reference to that project. Feel free to send a PR to remove those files.