For releases, make sure that the default value for scalaJSVersion in the
build matches the version of scalajs-cli.
This is a normal cross-compiled publish:
> +publishSigned
For each major version of Scala, identify the latest corresponding full version and run:
$ ./scripts/assemble-cli.sh <Scala.js full version> <Scala full version>
Then upload the produced archives (in pack/) to the website, using scp.