Add new parameter to release job: SCALA_BINARY_VER

Otherwise, the build for privately published build of Scalacheck
fails for binary-compatible releases (ie, non-RCs) with:

    unresolved dependency: org.scala-lang.modules#scala-parser-combinators_2.11.0;1.0.1: not found
Merge pull request #97 from retronym/topic/scalacheck-scala-binary-version

Add new parameter to release job: SCALA_BINARY_VER