This is where you'll get emails.  Like I say near the bottom.  Loop through this list to render emails to send.  For each email in this list, it links to the packages that this person is watching.

You should do this after already filtering through the packages finding out which ones have updates.

In the email loop, if there is one or more package that needs updates, you can then send a single email with all the updates of all dependencies of all subscribed packages.