Update sbt to 1.3.1, mima to 0.6.1

Author: lrytz

build.sbt

@@ -6,6 +6,6 @@ licenses            := Seq(("Apache-2.0", url("https://www.apache.org/licenses/L
 
 addSbtPlugin("com.typesafe.sbt" % "sbt-osgi" % "0.9.5")
 addSbtPlugin("de.heikoseeberger" % "sbt-header" % "5.2.0")
-addSbtPlugin("com.typesafe" % "sbt-mima-plugin" % "0.6.0")
+addSbtPlugin("com.typesafe" % "sbt-mima-plugin" % "0.6.1")
 addSbtPlugin("com.dwijnand" % "sbt-travisci" % "1.2.0")   // set scalaVersion and crossScalaVersions
 addSbtPlugin("com.geirsson" % "sbt-ci-release" % "1.3.2") // set version, scmInfo, publishing settings

project/build.properties

@@ -1 +1 @@
-sbt.version=1.3.0
+sbt.version=1.3.1