Update scala3-library to 3.3.6

Author: typelevel-steward[bot]

build.sbt

@@ -18,7 +18,7 @@ ThisBuild / tlSonatypeUseLegacyHost := false
 ThisBuild / tlSitePublishBranch := Some("main")
 
 val Scala213 = "2.13.16"
-ThisBuild / crossScalaVersions := Seq(Scala213, "3.3.3")
+ThisBuild / crossScalaVersions := Seq(Scala213, "3.3.6")
 ThisBuild / scalaVersion := Scala213 // the default Scala
 
 lazy val root = tlCrossRootProject.aggregate(core, mtl, testkit)