Update to .NET 10, VS 18, and include workflow in solution

Upgrade build to .NET 10, update to Visual Studio 18, and add workflow file to solution items.

.NET and Visual Studio version updates
  -- Update GitHub Actions workflow to use .NET 10.0.x (prerelease) instead of 8.0.x for building and packing.
  -- Update SmartValidations.sln to use Visual Studio Version 18 instead of 17.

Solution file improvements
  -- Add .github/workflows/smart-validations.yml as a solution item in SmartValidations.sln.

Author: eglauko

.github/workflows/smart-validations.yml

@@ -18,7 +18,7 @@ jobs:
       - name: Setup .NET
         uses: actions/setup-dotnet@v3
         with:
-          dotnet-version: '8.0.x'
+          dotnet-version: '10.0.x'
           include-prerelease: true
 
       - name: Build and pack SmartValidations

SmartValidations.sln

@@ -1,7 +1,7 @@
 
 Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio Version 17
-VisualStudioVersion = 17.0.31903.59
+# Visual Studio Version 18
+VisualStudioVersion = 18.3.11310.294 d18.3
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "RoyalCode.SmartValidations", "RoyalCode.SmartValidations\RoyalCode.SmartValidations.csproj", "{70F02EEE-23ED-447F-9543-F2A31D8149DC}"
 EndProject
@@ -11,6 +11,7 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = ".items", ".items", "{132AE6
 	ProjectSection(SolutionItems) = preProject
 		Directory.Build.props = Directory.Build.props
 		libs.targets = libs.targets
+		.github\workflows\smart-validations.yml = .github\workflows\smart-validations.yml
 	EndProjectSection
 EndProject
 Global