RepositoryUrl in nugets still points to old Xamarin (https://github.com/xamarin/AndroidX.git)

I noticed that the RepositoryUrl in nugets still points to [old xamarin/AndroidX](https://github.com/dotnet/android-libraries/blob/f3eafd8e3b565c1677f1622e6be322a1ac6b297f/Directory.Build.props#L3) instead of new dotnet/android-libraries.

So a small change to `https://github.com/dotnet/android-libraries.git` would be nice.