webapp-runner: 10.1.28.0 -> 10.1.31.0 (#990)

build.sbt

@@ -84,7 +84,7 @@ lazy val warRunner_6_0 =
         ),
       crossPaths := false, // exclude Scala suffix from artifact names
       autoScalaLibrary := false, // exclude scala-library from dependencies
-      libraryDependencies += "com.heroku" % "webapp-runner" % "10.1.28.0"
+      libraryDependencies += "com.heroku" % "webapp-runner" % "10.1.31.0"
     )
 
 lazy val sbtWar =