Update to .NET SDK 10 and revise toolkit requirements

Bump .NET SDK version to 10.0.100 in global.json and update NuGet operations to use 10.0.x in CI workflow. Simplify MVVM Toolkit error message to recommend using the latest .NET SDK version.

Author: Sergio0694

.github/workflows/ci-build.yml

@@ -24,7 +24,7 @@ env:
   # The version of .NET to use just for NuGet package operations.
   # This doesn't have to be exactly in sync with the .NET SDK
   # version defined in 'global.json', as it's not used for builds.
-  DOTNET_NUGET_VERSION: ${{ '9.0.x' }}
+  DOTNET_NUGET_VERSION: ${{ '10.0.x' }}
 
 jobs:
 

global.json

@@ -1,6 +1,6 @@
 {
   "sdk": {
-    "version": "9.0.306",
+    "version": "10.0.100",
     "rollForward": "latestFeature",
     "allowPrerelease": false
   }

src/CommunityToolkit.Mvvm/CommunityToolkit.Mvvm.WindowsSdk.targets

@@ -82,7 +82,7 @@
       Condition="'@(_MvvmToolkitCompatibleWindowsSdkPackages)' == ''"
       Code="MVVMTKCFG0003"
       HelpLink="https://aka.ms/mvvmtoolkit/errors/mvvmtkcfg0003"
-      Text="This version of the MVVM Toolkit requires 'Microsoft.Windows.SDK.NET.Ref' version '$(_MvvmToolkitWindowsSdkPackageRequired)' or later. Please update the .NET SDK in use to 8.0.405 (or later) or 9.0.102 (or later). Alternatively, use a temporary 'Microsoft.Windows.SDK.NET.Ref' reference, which can be done by setting the 'WindowsSdkPackageVersion' property in your .csproj file. For your project configuration, it is recommended to set the package version to '$(_MvvmToolkitWindowsSdkPackageRecommended)'." />
+      Text="This version of the MVVM Toolkit requires 'Microsoft.Windows.SDK.NET.Ref' version '$(_MvvmToolkitWindowsSdkPackageRequired)' or later. Please update the .NET SDK in use to the latest version. Alternatively, use a temporary 'Microsoft.Windows.SDK.NET.Ref' reference, which can be done by setting the 'WindowsSdkPackageVersion' property in your .csproj file. For your project configuration, it is recommended to set the package version to '$(_MvvmToolkitWindowsSdkPackageRecommended)'." />
   </Target>
 
 </Project>