deps: use sbt 1.9.3 for the community build

Author: ckipp01

Diff for: community-build/src/scala/dotty/communitybuild/projects.scala

@@ -140,7 +140,7 @@ final case class SbtCommunityProject(
       case Some(ivyHome) => List(s"-Dsbt.ivy.home=$ivyHome")
       case _ => Nil
     extraSbtArgs ++ sbtProps ++ List(
-      "-sbt-version", "1.9.0",
+      "-sbt-version", "1.9.3",
       "-Dsbt.supershell=false",
       s"-Ddotty.communitybuild.dir=$communitybuildDir",
       s"--addPluginSbtFile=$sbtPluginFilePath"