Give one more GB of memory to sbt on the CI.
Give one more GB of memory to sbt on the CI.

The bootstrap job in 2.10.2 almost consistently runs out of memory.

sjrd/scala-js,SebsLittleHelpers/scala-js,gzm0/scala-js,gzm0/scala-js,sjrd/scala-js,scala-js/scala-js,sjrd/scala-js,SebsLittleHelpers/scala-js,nicolasstucki/scala-js,nicolasstucki/scala-js,scala-js/scala-js,scala-js/scala-js