Update jetty-client to 12.0.21

Author: scala-steward

project/Commons.scala

@@ -30,7 +30,7 @@ object Commons extends ProjectGroup("commons") {
   val scalatestVersion = "3.2.19"
   val scalatestplusScalacheckVersion = "3.2.14.0"
   val scalacheckVersion = "1.18.1"
-  val jettyVersion = "12.0.20"
+  val jettyVersion = "12.0.21"
   val mongoVersion = "5.5.0"
   val springVersion = "5.3.39"
   val typesafeConfigVersion = "1.4.3"