Make sure all new packages have been mirrored to dotnet-public once per year

Every time we bump major version, we get a set of “new” packages, since packages like Microsoft.DotNet.Web.ItemTemplates.7.0 have the Major version in their name. This means someone needs to manually mirror these packages to dotnet-public so that further versions on nuget.org get auto-mirrored. We should have an automatic process to pick these up (along with new OOB package that might come along in a major release) so that we don’t have to remember to do this manually every year.

[michellemcdaniel]

In the staging pipeline, we have test feeds that we create on the fly to end-to-end test our publishing code. I’m sure we could follow that pattern. @jonfortescue worked on that and between him and me, we could walk someone through the process (all the code already exists, it would just be a matter of reusing it and hooking it all up).

[garath]

We have the same issue with e.g. https://www.nuget.org/packages/Microsoft.NET.Workload.Emscripten.Manifest-7.0.100 which is also not on dotnet-public right now.

@akoeplinger I have just pushed all versions to dotnet-public.