Update sbt-assembly to 2.3.1

Author: scala-steward

project/plugins.sbt

@@ -10,5 +10,5 @@ addSbtPlugin("com.github.sbt" % "sbt-protobuf" % "0.8.2")
 addSbtPlugin("com.typesafe" % "sbt-mima-plugin" % "1.1.4")
 addSbtPlugin("com.eed3si9n" % "sbt-buildinfo" % "0.13.1")
 addSbtPlugin("com.eed3si9n" % "sbt-projectmatrix" % "0.11.0")
-addSbtPlugin("com.eed3si9n" % "sbt-assembly" % "2.2.0")
+addSbtPlugin("com.eed3si9n" % "sbt-assembly" % "2.3.1")
 addSbtPlugin("org.jetbrains.scala" % "sbt-ide-settings" % "1.1.3")