Updating Basic.Reference.Assemblies going forward

[jaredpar]

When this project first started there were only a few Target Frameworks so having Basic.Reference.Assemblies.nupkg contain all of them was reasonable. Now though the number of target frameworks has increased significantly and having them all included is getting a bit unweildy. Mostly because the package size is getting to big to be reasonably used.

Going forward going to fix this by doing the following:

• Continuing to maintain a NuPkg for every supported target framework. So if you want netstandard1.3 it will still be there, just as a stand alone package
• Having only three target frameworks in Basic.Reference.Assemblies
  • netstandard2.0
  • net472 which represents the most prevalent .NET Framework target
  • The .NET Core target framework for latest RTM

[jaredpar]

After thinking a bit more the breakdown is going to be the following:

• net472 - this is effectively the latest .NET Framework
• netstandard2.0 - this is useful when you have to flip between .NET Framework and .NET Core
• .NET Core LTS: at this moment that is net6.0