Update logback-classic to 1.5.6 (#217)

Co-authored-by: lunatech-scala-steward[bot] <166295259+lunatech-scala-steward[bot]@users.noreply.github.com>

Author: lunatech-scala-steward[bot]

build.sbt

@@ -7,7 +7,7 @@ ThisBuild / organizationName := "lunatech"
 
 lazy val V = new {
   val circe     = "0.14.6"
-  val logback   = "1.5.5"
+  val logback   = "1.5.6"
   val pekko     = "1.0.2"
   val pekkoHttp = "1.0.1"
   val scalatest = "3.2.18"