Bump scala version to 2.13.9

To mitigate security vulnerability in scala-library

Author: spenes

modules/main/src/test/scala/com/snowplowanalytics/s3/loader/serializers/GZipSerializerSpec.scala

@@ -42,8 +42,8 @@ class GZipSerializerSpec extends Specification {
       cleanup()
 
       val binaryInputs = List(
-        List("A", "B", 1000, "a", "b").mkString("\t").getBytes.asRight,
-        List("X", "Y", 2000, "x", "y").mkString("\t").getBytes.asRight
+        (List("A", "B", 1000, "a", "b"):List[Any]).mkString("\t").getBytes.asRight,
+        (List("X", "Y", 2000, "x", "y"):List[Any]).mkString("\t").getBytes.asRight
       )
 
       val serializationResult =

project/BuildSettings.scala

@@ -36,7 +36,7 @@ object BuildSettings {
   // Basic settings for our app
   lazy val basicSettings = Seq(
     organization :=  "com.snowplowanalytics",
-    scalaVersion :=  "2.13.6",
+    scalaVersion :=  "2.13.9",
     description  := "Load the contents of a Kinesis stream topic to S3",
     resolvers             ++= Dependencies.resolvers,
     ThisBuild / dynverVTagPrefix := false,