Add 3rdPartyNotices to package

[AArnott]

Now that you are shipping additional Microsoft DLLs in the nupkg, I wonder whether they require adding some legal text as well. Perhaps it is enough that the version resources of the DLLs themselves carry Microsoft copyright notices, and that Nerdbank.GitVersioning.nuspec contains <license type="expression">MIT</license> which apparently matches how Microsoft licenses those DLLs.

Originally posted by @KalleOlaviNiemitalo in #589 (comment)

We should look at other 3rd party files that are included in the package (if any) as well.

[AArnott]

Closed by 443d422