[release/8.0.1xx-preview3] [net8.0] Remove support for .NET 6.

[vs-mobiletools-engineering-service2]

Context: https://dotnet.microsoft.com/platform/support/policy/maui

A major version of .NET MAUI receives support for a minimum of 6
months after a successor (the next major release) ships. For
example, .NET MAUI 6.0 will be supported for 6 months after .NET
MAUI 7.0 ships. Similarly, .NET MAUI 7.0 will receive support for 6
months after .NET MAUI 8.0 ships.

By the time .NET 8 GA ships, .NET 6 MAUI projects will not be supported.

Remove .NET 6 support from our .NET 8 workloads.

Backport of #17901

[vs-mobiletools-engineering-service2]

✅ API diff for current PR / commit

Legacy Xamarin (No breaking changes)

• iOS (no change detected)
• tvOS (no change detected)
• watchOS (no change detected)
• macOS (no change detected)

NET (empty diffs)

• iOS: (empty diff detected)
• tvOS: (empty diff detected)
• MacCatalyst: (empty diff detected)
• macOS: (empty diff detected)

✅ API diff vs stable

Legacy Xamarin (No breaking changes)

• iOS: vsdrops gist (No breaking changes)
• tvOS: vsdrops gist (No breaking changes)
• watchOS: vsdrops gist (No breaking changes)
• macOS: vsdrops gist (No breaking changes)

.NET (No breaking changes)

• iOS: vsdrops gist (No breaking changes)
• tvOS: vsdrops gist (No breaking changes)
• MacCatalyst: vsdrops gist (No breaking changes)
• macOS: vsdrops gist (No breaking changes)
• Microsoft.iOS vs Microsoft.MacCatalyst: vsdrops gist

Legacy Xamarin (stable) vs .NET

• iOS: vsdrops gist
• tvOS: vsdrops gist
• macOS: vsdrops gist

✅ Generator diff

Generator diff is empty

Pipeline on Agent
Hash: 2bf0f63c4f032ee0412eaa5ab16d11a5be4451ea [PR build]

[vs-mobiletools-engineering-service2]

💻 [PR Build] Tests on macOS M1 - Mac Big Sur (11.5) passed 💻

✅ All tests on macOS M1 - Mac Big Sur (11.5) passed.

Pipeline on Agent
Hash: 2bf0f63c4f032ee0412eaa5ab16d11a5be4451ea [PR build]

[vs-mobiletools-engineering-service2]

💻 [PR Build] Tests on macOS M1 - Mac Ventura (13.0) passed 💻

✅ All tests on macOS M1 - Mac Ventura (13.0) passed.

Pipeline on Agent
Hash: 2bf0f63c4f032ee0412eaa5ab16d11a5be4451ea [PR build]

[vs-mobiletools-engineering-service2]

📚 [PR Build] Artifacts 📚

Packages generated

View packages

• Microsoft.iOS.Bundle.16.2.456-ci.pr.gh17922.pkg
• Microsoft.iOS.Ref.16.2.456-ci.pr.gh17922.nupkg
• Microsoft.iOS.Runtime.ios-arm64.16.2.456-ci.pr.gh17922.nupkg
• Microsoft.iOS.Runtime.iossimulator-arm64.16.2.456-ci.pr.gh17922.nupkg
• Microsoft.iOS.Runtime.iossimulator-x64.16.2.456-ci.pr.gh17922.nupkg
• Microsoft.iOS.Sdk.16.2.456-ci.pr.gh17922.nupkg
• Microsoft.iOS.Templates.16.2.456-ci.pr.gh17922.nupkg
• Microsoft.iOS.Windows.Sdk.16.2.456-ci.pr.gh17922.nupkg
• Microsoft.MacCatalyst.Bundle.16.2.456-ci.pr.gh17922.pkg
• Microsoft.MacCatalyst.Ref.16.2.456-ci.pr.gh17922.nupkg
• Microsoft.MacCatalyst.Runtime.maccatalyst-arm64.16.2.456-ci.pr.gh17922.nupkg
• Microsoft.MacCatalyst.Runtime.maccatalyst-x64.16.2.456-ci.pr.gh17922.nupkg
• Microsoft.MacCatalyst.Sdk.16.2.456-ci.pr.gh17922.nupkg
• Microsoft.MacCatalyst.Templates.16.2.456-ci.pr.gh17922.nupkg
• Microsoft.macOS.Bundle.13.1.456-ci.pr.gh17922.pkg
• Microsoft.macOS.Ref.13.1.456-ci.pr.gh17922.nupkg
• Microsoft.macOS.Runtime.osx-arm64.13.1.456-ci.pr.gh17922.nupkg
• Microsoft.macOS.Runtime.osx-x64.13.1.456-ci.pr.gh17922.nupkg
• Microsoft.macOS.Sdk.13.1.456-ci.pr.gh17922.nupkg
• Microsoft.macOS.Templates.13.1.456-ci.pr.gh17922.nupkg
• Microsoft.NET.Sdk.iOS.Manifest-8.0.100-preview.3.16.2.456-ci.pr.gh17922.nupkg
• Microsoft.NET.Sdk.MacCatalyst.Manifest-8.0.100-preview.3.16.2.456-ci.pr.gh17922.nupkg
• Microsoft.NET.Sdk.macOS.Manifest-8.0.100-preview.3.13.1.456-ci.pr.gh17922.nupkg
• Microsoft.NET.Sdk.tvOS.Manifest-8.0.100-preview.3.16.1.1244-ci.pr.gh17922.nupkg
• Microsoft.NET.Workload.iOS.16.2.456-ci.pr.gh17922.msi
• Microsoft.tvOS.Bundle.16.1.1244-ci.pr.gh17922.pkg
• Microsoft.tvOS.Ref.16.1.1244-ci.pr.gh17922.nupkg
• Microsoft.tvOS.Runtime.tvos-arm64.16.1.1244-ci.pr.gh17922.nupkg
• Microsoft.tvOS.Runtime.tvossimulator-arm64.16.1.1244-ci.pr.gh17922.nupkg
• Microsoft.tvOS.Runtime.tvossimulator-x64.16.1.1244-ci.pr.gh17922.nupkg
• Microsoft.tvOS.Sdk.16.1.1244-ci.pr.gh17922.nupkg
• Microsoft.tvOS.Templates.16.1.1244-ci.pr.gh17922.nupkg
• xamarin.ios-16.2.1.456.pkg
• xamarin.mac-9.1.1.456.pkg

Pipeline on Agent XAMBOT-1033.Ventura
Hash: 2bf0f63c4f032ee0412eaa5ab16d11a5be4451ea [PR build]

[vs-mobiletools-engineering-service2]

🚀 [CI Build] Test results 🚀

Test results

✅ All tests passed on VSTS: simulator tests.

🎉 All 219 tests passed 🎉

Tests counts

✅ bcl: All 69 tests passed. Html Report (VSDrops) Download
✅ cecil: All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests: All 1 tests passed. Html Report (VSDrops) Download
✅ fsharp: All 7 tests passed. Html Report (VSDrops) Download
✅ framework: All 8 tests passed. Html Report (VSDrops) Download
✅ generator: All 2 tests passed. Html Report (VSDrops) Download
✅ interdependent_binding_projects: All 7 tests passed. Html Report (VSDrops) Download
✅ install_source: All 1 tests passed. Html Report (VSDrops) Download
✅ introspection: All 8 tests passed. Html Report (VSDrops) Download
✅ linker: All 65 tests passed. Html Report (VSDrops) Download
✅ mac_binding_project: All 1 tests passed. Html Report (VSDrops) Download
✅ mmp: All 2 tests passed. Html Report (VSDrops) Download
✅ mononative: All 6 tests passed. Html Report (VSDrops) Download
✅ monotouch: All 25 tests passed. [attempt 2] Html Report (VSDrops) Download
✅ msbuild: All 2 tests passed. Html Report (VSDrops) Download
✅ mtouch: All 1 tests passed. Html Report (VSDrops) Download
✅ xammac: All 3 tests passed. Html Report (VSDrops) Download
✅ xcframework: All 8 tests passed. Html Report (VSDrops) Download
✅ xtro: All 2 tests passed. Html Report (VSDrops) Download

Pipeline on Agent
Hash: 2bf0f63c4f032ee0412eaa5ab16d11a5be4451ea [PR build]