docs: added an upgrade guide for v1.10.0 (#4013)

* docs: added an upgrade guide for v1.10.0

* removed redis update command

* small text fix

* Update 1-10-0.md

---------

Co-authored-by: Oliver Windall Juhl <59018053+olivermrbl@users.noreply.github.com>

docs/content/development/events/create-module.md

@@ -192,37 +192,6 @@ class CustomEventBus extends AbstractEventBusModuleService {
 }
 ```
 
-### (optional) retrieveSubscribers
-
-This method is also implemented in the `AbstractEventBusModuleService` class. This section explains how you can override it to implement your custom logic, if necessary.
-
-The `retrieveSubscribers` method is used to retrieve the subscribers to a specific event. If there are no subscribers to an event, the event is not stored in the database or processed by the event bus module.
-
-The `retrieveSubscribers` method accepts one parameter, which is the name of the event. It should return an array of objects of the following type:
-
-```ts
-type SubscriberDescriptor = {
-  id: string
-  subscriber: Subscriber
-}
-```
-
-Where:
-
-- `id` is a string that is the ID of a subscriber.
-- `subscriber` is a subscriber class.
-
-For example, here's how the `retrieveSubscribers` is implemented in the `AbstractEventBusModuleService`:
-
-```ts title=services/event-bus-custom.ts
-class CustomEventBus extends AbstractEventBusModuleService {
-  // ...
-  retrieveSubscribers(event: string | symbol) {
-    return this.eventToSubscribersMap_.get(event)
-  }
-}
-```
-
 ---
 
 ## Step 3: Export the Service