Publish Scala 2.13.0 for 1.14.0

[ashawley]

I verified that the following works locally from sbt:

> ++2.13.0
> jvm/package
> js/package

That will publish Scala 2.13 and Scalajs 0.6.x for 2.13.

Publishing Scalajs for 1.0.0-M8 for 2.12 and 2.13, also works. First, start sbt with:

$ env SCALAJS_VERSION=1.0.0-M8 sbt

Then:

> ++2.12.6
> js/package
> ++2.13.0
> js/package

May require #475 for publish to work, though.

[rickynils]

I have now published 2.13 builds of ScalaCheck 1.14.0.

Thanks @ashawley