Update sbt-mima-plugin to 0.9.1 (#131)

Author: scala-steward

build.sbt

@@ -9,6 +9,6 @@ developers          := List(Developer("", "", "", url("https://scala-lang.org"))
 
 addSbtPlugin("com.typesafe.sbt" % "sbt-osgi" % "0.9.6")
 addSbtPlugin("de.heikoseeberger" % "sbt-header" % "5.6.0")
-addSbtPlugin("com.typesafe" % "sbt-mima-plugin" % "0.9.0")
+addSbtPlugin("com.typesafe" % "sbt-mima-plugin" % "0.9.1")
 addSbtPlugin("com.dwijnand" % "sbt-travisci" % "1.2.0")   // set scalaVersion and crossScalaVersions
 addSbtPlugin("com.geirsson" % "sbt-ci-release" % "1.5.7") // set version, scmInfo, publishing settings