Release 7.1.0 - Upgrade to .NET Core 3.x

Upgrade all LiteX Sms packages to .NET Core 3.x
Upgrade all dependent Microsoft packages to .NET Core 3.x
Upgrade all dependent packages (SDKs) to the latest version

Author: a-patel

README.md

@@ -20,11 +20,12 @@ LiteXStorage is an interface to unify the programming model for various storage
 - [Kvpbase](docs/Kvpbase.md) - deprecated
 
 #### Documents
-- [Old Docs - Version 6.x.x and before](README - 6.x.x and before.md)
+- [Old Docs - Version 6.x.x and before](https://github.com/a-patel/LiteXStorage/blob/master/README%20-%206.x.x%20and%20before.md)
 - Refer example code for more details
 
 
 ## Features :pager:
+- Multiple provider support (using provider factory)
 - Create container or bucket
 - Get Shared Access Signature (SAS) URL
 - Upload Blobb file