- Add Sparkle as an SPM dependency and wire up an updater UI
- Add UpdaterController (UpdaterController.swift)
- Add a "Check for Updates..." menu command wired to the updater
- Add appcast.xml and update Info.plist with SUFeedURL and SUPublicEDKey
- Add localized menu string "Check for Updates..." to all language files.
- Bump version to 2.2.2 (44).