Update to use contract nuget

Author: clairernovotny

Directory.Build.targets

@@ -1,12 +1,4 @@
 <Project>
-
-  <PropertyGroup>
-    <WindowsWinmdFile Condition="Exists('$(MSBuildProgramFiles32)\Windows Kits\10\UnionMetadata\$(TargetPlatformVersion)\Windows.winmd')">$(MSBuildProgramFiles32)\Windows Kits\10\UnionMetadata\$(TargetPlatformVersion)\Windows.winmd</WindowsWinmdFile>
-  </PropertyGroup>
-
-  <ItemGroup>
-    <Reference Update="Windows" Private="false" HintPath="$(WindowsWinmdFile)" />
-  </ItemGroup>
 
   <PropertyGroup>
     <Product Condition="'$(IsTypesProject)' != 'true'">$(Product) ($(Configuration))</Product>

OSVersionHelper/OSVersionHelper.csproj

@@ -8,7 +8,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <Reference Include="Windows" />
+    <PackageReference Include="Microsoft.Windows.SDK.Contracts" Version="10.0.19041.1" PrivateAssets="all" />
   </ItemGroup>
 
 </Project>