Set same cross Scala versions in all (sub)projects

Allows cross versioned execution of tasks without prior
navigation to sub-project.

build.sbt

@@ -1,13 +1,20 @@
 sourceDirectory := file("dummy source directory")
 
+scalaVersionSettings
+
 // When bumping to 1.14.1, remember to set mimaPreviousArtifacts to 1.14.0
 lazy val versionNumber = "1.14.0"
 
 lazy val isRelease = false
 
 lazy val travisCommit = Option(System.getenv().get("TRAVIS_COMMIT"))
 
-lazy val sharedSettings = MimaSettings.settings ++ Seq(
+lazy val scalaVersionSettings = Seq(
+  scalaVersion := "2.12.0",
+  crossScalaVersions := Seq("2.10.6", "2.11.8", scalaVersion.value)
+)
+
+lazy val sharedSettings = MimaSettings.settings ++ scalaVersionSettings ++ Seq(
 
   name := "scalacheck",
 
@@ -35,10 +42,6 @@ lazy val sharedSettings = MimaSettings.settings ++ Seq(
     username, password
   )).toSeq,
 
-  scalaVersion := "2.12.0",
-
-  crossScalaVersions := Seq("2.10.6", "2.11.8", "2.12.0"),
-
   unmanagedSourceDirectories in Compile += (baseDirectory in LocalRootProject).value / "src" / "main" / "scala",
 
   unmanagedSourceDirectories in Test += (baseDirectory in LocalRootProject).value / "src" / "test" / "scala",