Enable show release notes

[timtmok]

The code to show release notes has been disabled by default. This means that the action is hidden and release notes are not shown after an update.

It's possible to retrieve the release notes from the GitHub release description and parse it for the release notes section. The GitHub API does not require an access token for retrieving the release by tag name. https://docs.github.com/en/rest/releases/releases?apiVersion=2022-11-28#get-a-release-by-tag-name

• Update product contribution (update.ts) to use Positron versions when deciding whether to show release notes
• Update releaseNotesEditor.ts#loadReleaseNotes to retrieve release description for version and parse it for release notes

[juliasilge]

Related to #5722 where we outline some of our aspirations around release notes.

Note that we do not intend to have the GitHub release description be where we have human readable, nice release notes.