Update RELEASE_NOTES.md for 0.8.1 release (#161)

Co-authored-by: Aaron Stannard <[email protected]>

RELEASE_NOTES.md

@@ -1,13 +1,4 @@
-#### 0.8.0 April 16 2021 ####
+#### 0.8.1 April 20 2021 ####
 **Release of Akka.Persistence.Azure**
 
-- [Problem with implimentation of akka persistence contract](https://github.com/petabridge/Akka.Persistence.Azure/pull/143)
-- [Limiting batch size for table storage](https://github.com/petabridge/Akka.Persistence.Azure/pull/145)
-- [Bump AkkaVersion from 1.4.14 to 1.4.18](https://github.com/petabridge/Akka.Persistence.Azure/pull/148)
-- [Added settings for auto-initialize](https://github.com/petabridge/Akka.Persistence.Azure/pull/150)
-- [Upgrade WindowsAzure.Storage to Microsoft.Azure.Cosmos.Table and Azure.Storage.Blobs](https://github.com/petabridge/Akka.Persistence.Azure/pull/151)
-- [Added support to configure blob container public access level](https://github.com/petabridge/Akka.Persistence.Azure/pull/152) 
-- [Change the default public access type of auto-init containers to None](https://github.com/petabridge/Akka.Persistence.Azure/pull/154)
-- [Add DefaultAzureIdentity support for snapshot Azure Blob Storage](https://github.com/petabridge/Akka.Persistence.Azure/pull/155)
-
-See the README for documentation on how to use the latest features in Akka.Persistence.Azure: https://github.com/petabridge/Akka.Persistence.Azure#akkapersistenceazure
+- [Fix BlobContainerClient.CreateIfNotExists() returns null if container already exists](https://github.com/petabridge/Akka.Persistence.Azure/pull/160)