bump: kafka 1.20.4 (was 1.20.1) (akka#1805)

build.sbt

@@ -27,7 +27,7 @@ val KafkaVersionForDocs = "37"
 // This should align with the ScalaTest version used in the Akka testkit
 // https://github.com/akka/akka/blob/main/project/Dependencies.scala#L44
 val scalatestVersion = "3.2.16"
-val testcontainersVersion = "1.20.1"
+val testcontainersVersion = "1.20.4"
 val slf4jVersion = "2.0.16"
 // this depends on Kafka, and should be upgraded to such latest version
 // that depends on the same Kafka version, as is defined above