* Rollback `keytar-prebuild` and `electron` to compatible versions.
* Check if the targeted build platform is different from the platform that
is building the app. If that's the case, download the appropriate daemon.
The app now uses AppImage instead of .deb files for Linux. Thanks to this change, the app supports now auto-updates on Linux too.
The publishing workflow has been updated. It uses now the publishing mechanisms offered by electron-builder.
