Update mill-scalalib to 0.9.4 (#1825)

Author: scala-steward

project/Dependencies.scala

@@ -35,7 +35,7 @@ object Dependencies {
   val jjwtApi = "io.jsonwebtoken" % "jjwt-api" % "0.11.2"
   val jjwtImpl = "io.jsonwebtoken" % "jjwt-impl" % jjwtApi.revision
   val jjwtJackson = "io.jsonwebtoken" % "jjwt-jackson" % jjwtApi.revision
-  val millVersion = Def.setting(if (scalaBinaryVersion.value == "2.12") "0.6.3" else "0.9.3")
+  val millVersion = Def.setting(if (scalaBinaryVersion.value == "2.12") "0.6.3" else "0.9.4")
   val millScalalib = Def.setting("com.lihaoyi" %% "mill-scalalib" % millVersion.value)
   val monocleCore = "com.github.julien-truffaut" %% "monocle-core" % "2.1.0"
   val munit = "org.scalameta" %% "munit" % "0.7.20"