Draft: Update Release.md checklist

Vicky and Chuck reviewed this checklist on Sept 26th. We found a few items on here that are no longer being done in the same way, because of the change to Salesforce for support (e.g no bulk ticket updates), and some tasks that are shifting from support to marketing (mostly moving all of the announcement tasks to marketing). I split the Printing Press task into 2 (create the announcement and send the announcement) because it seems that the IM has been doing the Printing Press task (and also I don't want marketing to be responsible for the contents of the ASN, or even for deciding when it is 'done'). I removed the 'write a blog post in the case of a major release' because by the time we are doing this checklist, it is way too late to be starting that, and anyway, this happens only every other year and it just doesn't need to be on this checklist. TBH I think we could collapse more tasks into 'Marketing announces the release' but I am ok with leaving it as a bunch of separate checkboxes if others prefer that.