Use None/Include to ensure items are included in generated nupkg files.

[abbottdev]

Hopefully this is a straightforward one - I think the latest dependency fixes regressed the T4.BuildTools packages as the targets/props files weren't included in the nupkg.

Have run dotnet build locally and can confirm these changes ensure the props/targets are included.

This should address #176

Thanks!

[mhutch]

Thanks! I was certain these items were present in the build, so I did some digging and this is super weird. It's an oddity in the way NuGet packs items when multitargeting.

The issue appears to be that NuGet collects the None items from the outer build. However, the SDK only evaluates default item wildcards in the inner build, presumably for performance reasons.

Switching these from Update to Include means that the inner build will have duplicate copies of these items, which isn't great, but I don't see any cleaner way to work around the NuGet issue.

[mhutch]

The failing test appears to be an existing race that is hopefully fixed by #178

I'll land a couple other fixes then publish a new preview to nuget.org.