Generate reference packages using proper tooling: Microsoft.CodeAnalysis.CSharp 4.0.1 and System.IO.Pipelines 5.0.1

Co-authored-by: MichaelSimons <[email protected]>

Author: Copilot

src/referencePackages/src/microsoft.codeanalysis.csharp/4.0.1/Microsoft.CodeAnalysis.CSharp.4.0.1.csproj

@@ -0,0 +1,14 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFrameworks>netstandard2.0</TargetFrameworks>
+    <PackageVersion>4.0.1</PackageVersion>
+    <AssemblyName>Microsoft.CodeAnalysis.CSharp</AssemblyName>
+    <StrongNameKeyId>MicrosoftShared</StrongNameKeyId>
+  </PropertyGroup>
+
+  <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
+    <ProjectReference Include="../../microsoft.codeanalysis.common/4.0.1/Microsoft.CodeAnalysis.Common.4.0.1.csproj" />
+  </ItemGroup>
+
+</Project>