Update scalafmt worker to be compatible with Scala 3 (#1354)

* Update scalafmt worker to be compatible with Scala 3

Author: liucijus

scala/scalafmt/scalafmt/ScalafmtWorker.scala

@@ -7,14 +7,13 @@ import org.scalafmt.Scalafmt
 import org.scalafmt.config.Config
 import org.scalafmt.util.FileOps
 import scala.annotation.tailrec
-import scala.collection.JavaConverters._
 import scala.io.Codec
 
 object ScalafmtWorker extends Worker.Interface {
 
   def main(args: Array[String]): Unit = Worker.workerMain(args, ScalafmtWorker)
 
-  def work(args: Array[String]) {
+  def work(args: Array[String]): Unit = {
     val argName = List("config", "input", "output")
     val argFile = args.map{x => new File(x)}
     val namespace = argName.zip(argFile).toMap

scala/scalafmt/scalafmt_repositories.bzl

@@ -40,7 +40,7 @@ def scalafmt_repositories(
         "com_geirsson_metaconfig_core",
         "com_geirsson_metaconfig_typesafe_config",
     ]
-    if SCALA_MAJOR_VERSION == "2.13":
+    if SCALA_MAJOR_VERSION == "2.13" or SCALA_MAJOR_VERSION == "3.1":
         artifact_ids.append("io_bazel_rules_scala_scala_parallel_collections")
 
     repositories(