chore: bump Scala to 2.13.18 (#2515)

[He-Pin]

(cherry picked from commit 39276c9)

[He-Pin]

[11-18 10:01:24.755] [info] - must be established after initial lazy restart *** FAILED *** (24 seconds, 46 milliseconds)
[11-18 10:01:24.756] [info]   java.lang.AssertionError: assertion failed: timeout (20 seconds) during expectMsg while waiting for ping2
[11-18 10:01:24.756] [info]   at scala.Predef$.assert(Predef.scala:279)
[11-18 10:01:24.756] [info]   at org.apache.pekko.testkit.TestKitBase.expectMsg_internal(TestKit.scala:471)
[11-18 10:01:24.756] [info]   at org.apache.pekko.testkit.TestKitBase.expectMsg(TestKit.scala:457)
[11-18 10:01:24.756] [info]   at org.apache.pekko.testkit.TestKitBase.expectMsg$(TestKit.scala:457)
[11-18 10:01:24.756] [info]   at org.apache.pekko.testkit.TestKit.expectMsg(TestKit.scala:981)
[11-18 10:01:24.756] [info]   at org.apache.pekko.remote.artery.LateConnectSpec.$anonfun$new$2(LateConnectSpec.scala:59)
[11-18 10:01:24.756] [info]   at org.scalatest.OutcomeOf.outcomeOf(OutcomeOf.scala:85)
[11-18 10:01:24.756] [info]   at org.scalatest.OutcomeOf.outcomeOf$(OutcomeOf.scala:83)
[11-18 10:01:24.756] [info]   at org.scalatest.OutcomeOf$.outcomeOf(OutcomeOf.scala:104)
[11-18 10:01:24.756] [info]   at org.scalatest.Transformer.apply(Transformer.scala:22)
[11-18 10:01:24.756] [info]   at org.scalatest.Transformer.apply(Transformer.scala:20)
[11-18 10:01:24.756] [info]   at org.scalatest.wordspec.AnyWordSpecLike$$anon$3.apply(AnyWordSpecLike.scala:1240)
[11-18 10:01:24.756] [info]   at org.scalatest.TestSuite.withFixture(TestSuite.scala:196)
[11-18 10:01:24.756] [info]   at org.scalatest.TestSuite.withFixture$(TestSuite.scala:195)
[11-18 10:01:24.756] [info]   at org.apache.pekko.remote.artery.ArteryMultiNodeSpec.withFixture(ArteryMultiNodeSpec.scala:58)
[11-18 10:01:24.756] [info]   at org.scalatest.wordspec.AnyWordSpecLike.invokeWithFixture$1(AnyWordSpecLike.scala:1238)
[11-18 10:01:24.756] [info]   at org.scalatest.wordspec.AnyWordSpecLike.$anonfun$runTest$1(AnyWordSpecLike.scala:1250)
[11-18 10:01:24.756] [info]   at org.scalatest.SuperEngine.runTestImpl(Engine.scala:306)
[11-18 10:01:24.756] [info]   at org.scalatest.wordspec.AnyWordSpecLike.runTest(AnyWordSpecLike.scala:1250)
[11-18 10:01:24.756] [info]   at org.scalatest.wordspec.AnyWordSpecLike.runTest$(AnyWordSpecLike.scala:1232)
[11-18 10:01:24.756] [info]   at org.apache.pekko.testkit.PekkoSpec.runTest(PekkoSpec.scala:79)
[11-18 10:01:24.756] [info]   at org.scalatest.wordspec.AnyWordSpecLike.$anonfun$runTests$1(AnyWordSpecLike.scala:1309)
[11-18 10:01:24.756] [info]   at org.scalatest.SuperEngine.$anonfun$runTestsInBranch$1(Engine.scala:413)
[11-18 10:01:24.756] [info]   at scala.collection.immutable.List.foreach(List.scala:323)
[11-18 10:01:24.756] [info]   at org.scalatest.SuperEngine.traverseSubNodes$1(Engine.scala:401)
[11-18 10:01:24.756] [info]   at org.scalatest.SuperEngine.runTestsInBranch(Engine.scala:390)
[11-18 10:01:24.756] [info]   at org.scalatest.SuperEngine.$anonfun$runTestsInBranch$1(Engine.scala:427)
[11-18 10:01:24.757] [info]   at scala.collection.immutable.List.foreach(List.scala:323)
[11-18 10:01:24.757] [info]   at org.scalatest.SuperEngine.traverseSubNodes$1(Engine.scala:401)
[11-18 10:01:24.757] [info]   at org.scalatest.SuperEngine.runTestsInBranch(Engine.scala:396)
[11-18 10:01:24.757] [info]   at org.scalatest.SuperEngine.runTestsImpl(Engine.scala:475)
[11-18 10:01:24.757] [info]   at org.scalatest.wordspec.AnyWordSpecLike.runTests(AnyWordSpecLike.scala:1309)
[11-18 10:01:24.757] [info]   at org.scalatest.wordspec.AnyWordSpecLike.runTests$(AnyWordSpecLike.scala:1308)
[11-18 10:01:24.757] [info]   at org.apache.pekko.testkit.PekkoSpec.runTests(PekkoSpec.scala:79)
[11-18 10:01:24.757] [info]   at org.scalatest.Suite.run(Suite.scala:1114)
[11-18 10:01:24.757] [info]   at org.scalatest.Suite.run$(Suite.scala:1096)
[11-18 10:01:24.757] [info]   at org.apache.pekko.testkit.PekkoSpec.org$scalatest$wordspec$AnyWordSpecLike$$super$run(PekkoSpec.scala:79)
[11-18 10:01:24.757] [info]   at org.scalatest.wordspec.AnyWordSpecLike.$anonfun$run$1(AnyWordSpecLike.scala:1354)
[11-18 10:01:24.757] [info]   at org.scalatest.SuperEngine.runImpl(Engine.scala:535)
[11-18 10:01:24.757] [info]   at org.scalatest.wordspec.AnyWordSpecLike.run(AnyWordSpecLike.scala:1354)
[11-18 10:01:24.757] [info]   at org.scalatest.wordspec.AnyWordSpecLike.run$(AnyWordSpecLike.scala:1352)
[11-18 10:01:24.757] [info]   at org.apache.pekko.testkit.PekkoSpec.org$scalatest$BeforeAndAfterAll$$super$run(PekkoSpec.scala:79)
[11-18 10:01:24.757] [info]   at org.scalatest.BeforeAndAfterAll.liftedTree1$1(BeforeAndAfterAll.scala:213)
[11-18 10:01:24.757] [info]   at org.scalatest.BeforeAndAfterAll.run(BeforeAndAfterAll.scala:210)
[11-18 10:01:24.757] [info]   at org.scalatest.BeforeAndAfterAll.run$(BeforeAndAfterAll.scala:208)
[11-18 10:01:24.757] [info]   at org.apache.pekko.testkit.PekkoSpec.run(PekkoSpec.scala:79)
[11-18 10:01:24.757] [info]   at org.scalatest.tools.Framework.org$scalatest$tools$Framework$$runSuite(Framework.scala:321)
[11-18 10:01:24.757] [info]   at org.scalatest.tools.Framework$ScalaTestTask.execute(Framework.scala:517)
[11-18 10:01:24.757] [info]   at sbt.ForkMain$Run.lambda$runTest$1(ForkMain.java:414)
[11-18 10:01:24.757] [info]   at java.util.concurrent.FutureTask.run(FutureTask.java:266)
[11-18 10:01:24.757] [info]   at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
[11-18 10:01:24.757] [info]   at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
[11-18 10:01:24.757] [info]   at java.lang.Thread.run(Thread.java:750)

Unreleated

[He-Pin]

https://github.com/scala/scala/releases/tag/v2.13.18

@pjfanning cc

[pjfanning]

I've explained a number of times that doing scala updates in 1.x introduces a lot of work. Lots of CI builds in the other pekko modules will break. It is far from a priority for me to update Scala in 1.x.

[raboof]

I've explained a number of times that doing scala updates in 1.x introduces a lot of work. Lots of CI builds in the other pekko modules will break. It is far from a priority for me to update Scala in 1.x.

perhaps we should summarize this in CONTRIBUTING.md?