Merge pull request #439 from typelevel/update/scala-library-2.13.15

Update scala-library to 2.13.15

Author: rossabaker

build.sbt

@@ -152,7 +152,7 @@ lazy val docs = project
   .dependsOn(core.jvm, testing.jvm)
   .enablePlugins(TypelevelSitePlugin)
 
-val Scala213 = "2.13.14"
+val Scala213 = "2.13.15"
 
 // General Settings
 inThisBuild(