Remove net6.0 support from NetNamedPipe code gen.

Author: imcarolwang

src/dotnet-svcutil/lib/Microsoft.Svcutil.NamedPipeMetadataImporter/Microsoft.Svcutil.NamedPipeMetadataImporter.csproj

@@ -3,7 +3,7 @@
     <AssemblyVersionFile>$(IntermediateOutputPath)\$(TargetFramework)\$(MSBuildProjectName).$(TargetFramework).version.cs</AssemblyVersionFile>
   </PropertyGroup>
   <PropertyGroup>
-    <TargetFrameworks>net6.0;net8.0;$(NetFrameworkVersion)</TargetFrameworks>
+    <TargetFrameworks>net8.0;$(NetFrameworkVersion)</TargetFrameworks>
     <RootNamespace>Microsoft.Tools.ServiceModel.Svcutil</RootNamespace>
     <AssemblyName>$(MSBuildProjectName)</AssemblyName>
     <LangVersion>latest</LangVersion>

src/dotnet-svcutil/lib/src/Metadata/ServiceDescriptor.cs

@@ -100,15 +100,7 @@ public async Task ImportMetadataAsync(Action<WsdlImporter> onWsdlImporterCreated
             //if it's net.pipe url
             if (MetadataUrl != null && MetadataUrl.Scheme.Equals("net.pipe"))
             {
-                string tfn;
-                if (OperationalCtx == OperationalContext.Infrastructure)
-                {
-                    tfn = "net462";
-                }
-                else
-                {
-                    tfn = Environment.Version.Major >= 8 ? "net8.0" : "net6.0";
-                }
+                string tfn = OperationalCtx == OperationalContext.Infrastructure ? "net462" : "net8.0";
 
                 string toolPath = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);
                 Assembly assembly = Assembly.LoadFrom($"{toolPath}/{tfn}/Microsoft.Svcutil.NamedPipeMetadataImporter.dll");

src/dotnet-svcutil/lib/src/Shared/MSBuildProj.cs

@@ -551,7 +551,7 @@ public bool AddDependency(ProjectDependency dependency, bool copyInternalAssets
                 if(copyInternalAssets && dependency.AssemblyName == "dotnet-svcutil-lib")
                 {
                     string basePath;
-                    string[] frameworks = { "net6.0", "net8.0", "net462" };
+                    string[] frameworks = { "net8.0", "net462" };
                     switch (dependency.DependencyType)
                     {
                         case ProjectDependencyType.Binary:

src/dotnet-svcutil/lib/src/dotnet-svcutil-lib.csproj

@@ -62,7 +62,6 @@
   </ItemGroup>
   <Target Name="PackAdditonalDlls" AfterTargets="build">
     <ItemGroup>
-      <None Include="$([System.IO.Path]::GetFullPath('$(ArtifactsBinDir)\'))\Microsoft.Svcutil.NamedPipeMetadataImporter\$(Configuration)\net6.0\*.dll" Pack="true" PackagePath="net6.0" />
       <None Include="$([System.IO.Path]::GetFullPath('$(ArtifactsBinDir)\'))\Microsoft.Svcutil.NamedPipeMetadataImporter\$(Configuration)\net8.0\*.dll" Pack="true" PackagePath="net8.0" />
       <None Include="$([System.IO.Path]::GetFullPath('$(ArtifactsBinDir)\'))\Microsoft.Svcutil.NamedPipeMetadataImporter\$(Configuration)\net462\*.dll" Pack="true" PackagePath="net462" />
     </ItemGroup>