[Personalizer] Update readme (#22963)

Co-authored-by: orenmichaely <73134189+ormichae@users.noreply.github.com>

Author: orenmichaely

sdk/personalizer/README.md

@@ -10,7 +10,7 @@ is a cloud-based service that helps your applications choose the best content it
 Install the Azure Personalizer client library for .NET with [NuGet][nuget]:
 
 ```Powershell
-dotnet add package Azure.AI.Personalizer --version 1.1.0-beta.1
+dotnet add package Azure.AI.Personalizer --version 2.0.0-beta.1
 ```
 
 ## Key concepts