Update scala-compiler, scala-library to 2.13.8

Author: 47erbot

build.sbt

@@ -17,7 +17,7 @@ lazy val V = new {
   val github4s: String            = "0.28.5"
   val http4s: String              = "0.21.31"
   val runtime: String             = "0.6.4"
-  val scala: String               = "2.13.7"
+  val scala: String               = "2.13.8"
   val scala212: String            = "2.12.15"
   val scalacheck: String          = "1.15.4"
   val scalacheckShapeless: String = "1.3.0"