Exclude vcxproj from `nbgv install` impact
Exclude vcxproj from `nbgv install` impact

vcxproj doesn't support PackageReference, but when such an item exists it will try (and fail) after a package restore notices it.
We therefore need to suppress the item from such projects.

vcxproj _is_ supported by Nerdbank.GitVersioning, but it must be done by manual install of the package via packages.config for that project.

Fixes #533

AArnott/Nerdbank.GitVersioning,AArnott/Nerdbank.GitVersioning,AArnott/Nerdbank.GitVersioning