Fix blog post for 5.0: no need to Volo.Abp.EventBus.Boxes package anymore.

docs/en/Blog-Posts/2021-11-18 v5_0_Preview/POST.md

@@ -127,13 +127,7 @@ First of all, you need to have EF Core or MongoDB installed into your solution.
 
 #### Install the packages
 
-Install the new [Volo.Abp.EventBus.Boxes](https://www.nuget.org/packages/Volo.Abp.EventBus.Boxes) NuGet package to your database layer (to `EntityFrameworkCore` or `MongoDB` project) or to the host application. Open a command-line terminal at the root directory of your database (or host) project and execute the following command:
-
-````csharp
-abp add-package Volo.Abp.EventBus.Boxes
-````
-
-This will install the package and setup the ABP module dependency. This package depends on [DistributedLock.Core](https://www.nuget.org/packages/DistributedLock.Core) library which provides a distributed locking system for concurrency control in a distributed environment. There are [many distributed lock providers](https://github.com/madelson/DistributedLock#implementations), including Redis, SqlServer and ZooKeeper. You can use the one you like. Here, I will show the Redis provider.
+For the outbox & inbox functionality, ABP depends on [DistributedLock.Core](https://www.nuget.org/packages/DistributedLock.Core) library which provides a distributed locking system for concurrency control in a distributed environment. There are [many distributed lock providers](https://github.com/madelson/DistributedLock#implementations), including Redis, SqlServer and ZooKeeper. You can use the one you like. Here, I will show the Redis provider.
 
 Add [DistributedLock.Redis](https://www.nuget.org/packages/DistributedLock.Redis) NuGet package to your project, then add the following code into the ConfigureService method of your ABP module class: