Fix js/native support & bump sbt and plugins versions

[gourlaysama]

Naming the js/native projects by hand changed the produced artifactIds
(scala-parser-combinators-js_sjs0.6_2.12), and that breaks dependency resolution.

And then we can release 1.0.7! 🎉

[gourlaysama]

Upgrading scala-js to 0.6.20 breaks the build (because of scala-js/scala-js/issues/3128), so only 0.6.19.

[gourlaysama]

I triggered a test build here, but the automated publishing didn't do the right thing: scalaVersionsByJvm only encodes a (JVM version, Scala version) build matrix. That's not enough with scala-native now: we want to publish when on (java 8, scala 2.11, native), but not on (java 8, scala 2.11, jvm) and it cannot encode that.

That build matrix is becoming really ugly... 😞

[lrytz]

@gourlaysama it seems we have the same issue with scala-js.

Another issue with the current setup: the build runs +publishLocal, which overrides the explicit scalaVersion in the native project (https://github.com/scala/scala-parser-combinators/blob/1.0.x/build.sbt#L57). So the jdk 8 build actually published scala-parser-combinators_native0.3_2.12. Now there's no release for native and 2.12, and (I checked locally) the resulting jar contains only .class files, but no .nir files.

I need to come up with a cross versioning scheme that also supports js / native.

[lrytz]

FTR i have some WIP here: https://github.com/lrytz/sbt-scala-module/tree/platforms. Not yet working; I would basically like to completely disable / remove a project (js / native) if its crossScalaVersions (which is defined according to the current jvm version) is empty. I haven't found out how to get there yet.

It also needs sbt-doge (or sbt 1).

[SethTisue]

It seems to me that we both could and should just drop sbt 0.13 support.