Update DiffEngine.csproj

Author: SimonCropp

src/DiffEngine/DiffEngine.csproj

@@ -22,6 +22,6 @@
     <PackageReference Include="Nullable" Version="1.3.1" PrivateAssets="all" />
     <PackageReference Include="IndexRange" Version="1.0.2" PrivateAssets="All" />
     <PackageReference Include="System.Runtime.InteropServices.RuntimeInformation" Version="4.3.0" Condition="$(TargetFramework) == 'net461'" />
-    <PackageReference Include="System.Management" Version="7.0.0" />
+    <PackageReference Include="System.Management" Version="6.0.0" />
   </ItemGroup>
 </Project>