Update build definitions, packaging and build images for net11.0 #87

Add net11.0 to the build and packaging definitions, and remove net6.0, net8.0 and net9.0, which are out of Microsoft support when 2027.0 ships. The platform baseline is PB-2027.0, specified in Documentation/PlatformSupport.md in postsharp/PostSharp.

Breaking change

net6.0, net8.0 and net9.0 are no longer supported user target frameworks, and the packages no longer ship lib/ assets for them.

• A project that targets one of these frameworks resolves the netstandard2.0 asset when the package has one.
• PostSharp.Patterns.Xaml has no netstandard2.0 asset. A Windows Presentation Foundation application on .NET 8 or .NET 9 therefore finds no compatible asset. PostSharp.Patterns.Threading has the same limitation for its Windows-specific assets.
• The .NET 8 and .NET 9 SDKs are no longer supported at build time. The minimum is the .NET 10 SDK.

Upgrade to net10.0 or net11.0.

What was done

• Root.Defs.props:
  • Adds Net110Tfm and Net110WindowsTfm to the Tfm items, and net11.0 to the Full framework set.
  • Declares the .NET SDKs 10.0 (floor) and 11.0 (ceiling), with their minimal build numbers and compatible runtimes. The .NET 8.0 and 9.0 SDK entries are removed.
  • Reduces the in-job runtime fan-out to .NET 10.0 and 11.0.
• Build/PostSharp.Dll.props maps net11.0 and net11.0-* to the net10.0 assembly.
• The NuGet packages ship no net6.0, net8.0 or net9.0 asset. The lib/net10.0 assets serve net11.0 users, so no net11.0 asset is added (rule 8 of PlatformSupport.md). The .NET tools move from tools/net8.0 to tools/net10.0.
• Prepare.proj defaults to the .NET 10 SDK, and global.json pins 10.0.100.
• The build images are generated from eng/src/Program.cs by PostSharp.Engineering. They install the .NET 10.0.100 and 11.0.100-rc.1 SDKs.
  • SDK 6.0 is not kept. The runtime fan-out follows the supported runtimes, net10.0 and net11.0, so nothing executes on net6.0.

Implemented in postsharp/PostSharp#99. Stale documentation removed in postsharp/PostSharp#132.

Verification

The distribution is tested by PostSharp.Tests.DotNetSdk. It builds net10.0 and net11.0 applications with the .NET 10 and 11 SDKs on Windows and Linux, x64 and ARM64: postsharp/PostSharp.Tests.DotNetSdk#3.

Follow-up

• The .NET 11 release-candidate versions in Root.Defs.props move to the released build when .NET 11 ships (item 2 of Documentation/PB-2027.0-TODO.md).

— Claude for Gael