Merge pull request #213 from scala-steward/update/play-akka-http-server-2.9.8

Update play-akka-http-server, ... to 2.9.8

Author: mkurz

project/plugins.sbt

@@ -1,4 +1,4 @@
 // The Play plugin
-addSbtPlugin("com.typesafe.play" % "sbt-plugin" % "2.9.7")
+addSbtPlugin("com.typesafe.play" % "sbt-plugin" % "2.9.8")
 
 addSbtPlugin("org.scalameta" % "sbt-scalafmt" % "2.5.5")