use modern MiMa version

Author: SethTisue

.travis.yml

@@ -31,7 +31,7 @@ install:
   - unset SBT_OPTS
   - export JAVA_OPTS="-Xms2048M -Xmx2048M -Xss6M -XX:ReservedCodeCacheSize=256M"
 
-script: sbt -Dfile.encoding=UTF8 mimaReportBinaryIssues headerCheck packageBin doc
+script: sbt -Dfile.encoding=UTF8 compilerInterface/mimaReportBinaryIssues headerCheck packageBin doc
 
 before_cache:
   - find $HOME/.ivy2/cache -name "*-LM-SNAPSHOT*" -delete

project/plugins.sbt

@@ -1,4 +1,4 @@
 addSbtPlugin("org.scala-sbt" % "sbt-contraband" % "0.4.1")
-addSbtPlugin("com.typesafe" % "sbt-mima-plugin" % "0.3.0")
+addSbtPlugin("com.typesafe" % "sbt-mima-plugin" % "0.6.4")
 addSbtPlugin("de.heikoseeberger" % "sbt-header" % "5.4.0")
 addSbtPlugin("com.dwijnand" % "sbt-dynver" % "3.3.0")