Merge pull request #279 from Dwolla/update/scala-library-2.13.15

Update scala-library to 2.13.15

build.sbt

@@ -1,6 +1,6 @@
 lazy val V = new {
   val SCALA_2_12 = "2.12.20"
-  val SCALA_2_13 = "2.13.14"
+  val SCALA_2_13 = "2.13.15"
   val Scalas = Seq(SCALA_2_13, SCALA_2_12)
 }