Add Env class to dnup

Author: dsplaisted

src/Installer/dnup/dnup.csproj

@@ -24,6 +24,7 @@
     <Compile Include="$(RepoRoot)src\Cli\dotnet\Telemetry\CIEnvironmentDetectorForTelemetry.cs" LinkBase="Shared" />
     <Compile Include="$(RepoRoot)src\Cli\dotnet\Telemetry\EnvironmentDetectionRule.cs" LinkBase="Shared" />
     <Compile Include="$(RepoRoot)src\Cli\dotnet\Telemetry\ICIEnvironmentDetector.cs" LinkBase="Shared" />
+    <Compile Include="$(RepoRoot)src\Cli\Microsoft.DotNet.Cli.Utils\Env.cs" LinkBase="Shared" />
     <Compile Include="$(RepoRoot)src\Cli\Microsoft.DotNet.Cli.Utils\EnvironmentProvider.cs" LinkBase="Shared" />
     <Compile Include="$(RepoRoot)src\Cli\Microsoft.DotNet.Cli.Utils\Extensions\CollectionsExtensions.cs" LinkBase="Shared" />
     <Compile Include="$(RepoRoot)src\Cli\Microsoft.DotNet.Cli.Utils\IEnvironmentProvider.cs" LinkBase="Shared" />