v0.6.0

• Release notes are easier to read: bold and keys now render properly in
  "What's new" and Settings › About, and internal issue numbers no longer
  appear in them.
• The sidebar's update pill now shows what it wants at a glance: a ready
  update gets a highlighted row with Restart…, an update on offer shows
  Download…, and a download in progress shows a progress ring with a live
  percentage.