Always use latest targeting packs (#36718)
Always use latest targeting packs (#36718)

- also, only update latest `@(KnownFrameworkReference)` items
  - previously the updates applied e.g. to all Microsoft.NETCore.App items

nit: f8943595516f24cc44ca252adb2265caeb4d99bb@(KnownFrameworkReference)` comments
aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore