.NET 6 Support targeting iOS and Android with the .NET SDK

[marcpopMSFT]

This epic tracks the work to support targeting iOS and Android in the .NET SDK. This was generated from the work that was cut from #11165 as not in scope for .net 5

This includes work in the .NET SDK, MSBuild, and NuGet to support new TargetFrameworks, or other related work.

Open design issues: #11275

• dotnet tools X net5.0 dotnet tools targeting Windows APIs #12055 (optional for .NET 6)

External to Workloads

• Normalize TargetPlatformIdentifier casing
  • Windows
  • Android (.NET 6)
  • iOS and other Apple platforms (macOS, tvOS, watchOS) (.NET 6)
• Support platform-specific OS minimum version attributes, translating them to OSMinimumVersion if current target matches
  • WindowsMinimumVersion -- .NET 6
  • IOSMinimumVersion -- .NET 6
  • AndroidMinimumVersion -- .NET 6
• Set default TargetPlatformVersion based on TFI, TFV, and TPI
  • For Windows: Set default TargetPlatformVersion for Windows #11233
  • For iOS and Android (in the corresponding workloads) .NET 6
• iOS / Android workloads: Support sdk-style projects for iOS / Android
  • Default item globs
  • Other defaults, and integration into Microsoft.NET.Sdk

[marcpopMSFT]

No more planned work in this space for 6.0.1xx so closing out. We'll leave the specific tools item open.