WebSharper.D3 5.0.0-preview1

This is a preview release of WebSharper.D3 5.

Improvements

• Added .NET 5 support. .NET Core 3.1 and netstandard2.0 still supported.
• Use common Build script with WebSharper ecosystem.

Enhancements

• #16 #19 Updated bindings to 7.0.1