Pack does not identify net6.0-windows as TargetFramework

Description

When building "net6.0-windows" targeted projects, paket pack will not include the dll of that build in the nuget package.
When targeting "net6.0-windows7.0", it works.

Since paket.dependencies handles net6.0-windows alias properly, pack should do the same.

Found in version

The issue is present in the current 7.1.5 version.

Repro steps

1. Target a project to net6.0-windows

2. Build the project and create package using paket pack

3. Note that there is not net6 dll in lib folder of the nuget package.

Expected behavior

If paket resolves net6.0-windows to the latest version that is net6.0-windows7.0 as of now, it should package the net6.0-windows build into that resolved version too.

Another solution would be to add a warning/error message about recognizing the issue and suggesting the explicit targeting

Actual behavior

When building against net6.0-windows, no dll will be included in the package and nor will there be any warnings

Known workarounds

Explicitly building against net6.0-windows7.0 is working just fine.

Start by reproducing the issue with paket pack on a project targeting net6.0-windows, then compare it with net6.0-windows7.0. Done means the net6.0-windows build is included in the NuGet package, or the command emits a warning or error explaining the unsupported target.