Upgrade to .NET 5.x

Upgrade to .NET 5.x
Added multi-framework target support - .NET 5, .NET Core 3.1, .NET Standard 2.1 and .NET Standard 2.0
Update libraries and SDKs to the latest version.

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

8.0.0 - Multiple Provider support

Multiple provider support (using provider factory)

6.x.x - Before Multiple Provider support

Before multiple provider support (using provider factory)