Update scala-library to 2.12.20 (#485)

Author: scala-steward

project/Dependencies.scala

@@ -13,7 +13,7 @@ object Dependencies {
   object Versions {
     val Scala3            = "3.3.3"
     val Scala213          = "2.13.14"
-    val Scala212          = "2.12.19"
+    val Scala212          = "2.12.20"
     val EmbeddedKafka     = "3.7.1.1"
     val ConfluentPlatform = "7.7.0"
     val Slf4j             = "1.7.36"