Update scala-library to 2.13.15

Author: scala-steward-bot

build.sbt

@@ -103,7 +103,7 @@ val commonSettings = Def.settings(
   },
   scalacOptions ++= unusedWarnings,
   scalaVersion := scala212,
-  crossScalaVersions := scala212 :: "2.13.14" :: "3.3.3" :: Nil,
+  crossScalaVersions := scala212 :: "2.13.15" :: "3.3.3" :: Nil,
   (Compile / doc / scalacOptions) ++= {
     val tag = tagOrHash.value
     Seq(