issue with link to an Akka sample in pekko-sample-cluster-java README.md

The pekko-sample-cluster-java README.md docs refer to:

Distributed Workers With Akka - https://developer.lightbend.com/guides/akka-distributed-workers-java/

This seems to be non-existent. We have a Scala sample like this but not a Java one.

In #33, I'm changing the link to be to the existent Scala sample. Maybe, someone with time and an interest in Java support will write the Java equivalent.

Review the pekko-sample-cluster-java README.md entry for “Distributed Workers With Akka” and compare it with the existing Scala sample link. Check issue #33, which already proposes changing this reference; the documentation work is done when the README points to a valid sample and no longer references the nonexistent Java guide.

Written by the indexing model from the issue text.