Update winston, re-enable promotions when appropriate (Puppet Server 6.13.0)

(Initial planned release date: 2020-08-25)

• If this release was part of a PE release, re-enable FOSS promotions once that release is ready to ship. Note: while it might be reasonable to re-enable these after PE's stop-ship, oftentimes additional last minute things need to land in pe-pse or pe-puppetserver, which gets complicated if untagged versions of puppetserver have promoted. So for now, we usually wait until after the window for such emergency changes has ended.
• Update winston and any relevant Confluence pages with any changes needed in the release process.