docs: replace course reference to Akkademy (#2187)

Refs: lightbend/kalix#11423

docs/src/modules/java-protobuf/partials/eventsourced.adoc

@@ -15,4 +15,4 @@ In contrast with typical create, read, update (CRUD) systems, event sourcing all
 [sidebar]
 Event Sourced Entities offer strong consistency guarantees. Kalix distributes Entities across every instance of a stateful service deployment--at any given time, each Entity lives on exactly one instance. If a command for an Entity arrives to an instance not hosting that Entity, the command is forwarded by the Kalix Runtime to the one that contains that particular Entity. This forwarding is done transparently, your code does not need to know. Because each Entity lives on exactly one instance, messages can be handled sequentially. Hence, there are no concurrency concerns relating to Event Sourced Entities, each Entity handles one message at a time.
 
-TIP: To learn more about event sourcing, check out the free Lightbend Academy course, https://akkademy.akka.io/learn/courses/10/reactive-architecture6-cqrs-event-sourcing[Reactive Architecture: CQRS & Event Sourcing {tab-icon}, window="new"].
+TIP: To learn more about event sourcing, check out the free Akkademy course, https://akkademy.akka.io/learn/courses/10/reactive-architecture6-cqrs-event-sourcing[Reactive Architecture: CQRS & Event Sourcing {tab-icon}, window="new"].