Update Release notes

Author: StevenTCramer

Documentation/ReleaseNotes/Release3.0.0.md

@@ -19,4 +19,6 @@ Update Nuget Production Dependency:  TypeSupport now supports HashTables.
 ## Release 3.1.0
 
 AddBlazorState Extention method has been updated to automatically register all classes that inherit from `State<>`.
-   Thus we no longer need to explicitly register States.
+   Thus we no longer need to explicitly register States.
+
+Updated Mediator to 8.0 https://jimmybogard.com/mediatr-8-0-released/