Update sbt-shading to 2.1.1 (#375)

Author: scala-steward

project/plugins.sbt

@@ -3,4 +3,4 @@ addSbtPlugin("com.typesafe" % "sbt-mima-plugin" % "1.1.2")
 addSbtPlugin("org.scala-js" % "sbt-scalajs" % "1.12.0")
 addSbtPlugin("org.portable-scala" % "sbt-scalajs-crossproject" % "1.2.0")
 addSbtPlugin("org.scala-js" % "sbt-jsdependencies" % "1.0.2")
-addSbtPlugin("io.get-coursier" % "sbt-shading" % "2.1.0")
+addSbtPlugin("io.get-coursier" % "sbt-shading" % "2.1.1")