Release v3.21.0-beta.1 (#1866)

Improvements for all users:

• Moving a document to an ignored location (see
  https://github.com/cozy-labs/cozy-desktop/blob/master/core/config/.cozyignore
  and your local .cozyignore rules file) after another move would result in
  the first move being propagated to the remote Cozy and the document being
  desynchronized after that.
  From now on, the second move to the ignored location will cancel the first
  move and the client will correctly propagate a deletion to the remote Cozy.
• Deleting a file on your Cozy while moving it on your local filesystem with
  your client stopped would lead to the desynchronisation of the file. It would
  be deleted on your Cozy but would still exist on your local filesystem and all
  later modifications would not be propagated.
  We're now refusing the deletion because we believe the movement indicates a
  desire to keep the file and it seems easier for the user to understand and fix
  the situation if that was not the expected behavior. The file move will then
  be propagated to the remote Cozy and kept in sync.
• In some situations we can detect changes made on your remote Cozy on documents
  of which we haven't yet received the parent folders. We can't process orphaned
  documents so we require the parents of all documents before we allow
  processing those and if we don't have them, we'll issue an error that results
  in the "Synchronization incomplete" status message, literally blocking the
  synchronization process.
  We believe that most of those issues could resolve themselves by merely
  refusing the orphan change and synchronizing the other changes so we've
  decided not to block the synchronization process anymore when we encounter
  orphan changes.
• We detected that the remote watcher whose role is to detect, fetch and analyze
  changes coming from your remote Cozy could fail without the synchronization
  process stopping and alerting you. This means that in such cases, the changes
  made on your local filesystem would still be detected and potentially
  propagated to your remote Cozy but the changes made remotely would not be
  applied locally until a client restart.
  We've refactored the life-cycle management of the whole synchronization
  process and the remote watcher and we made sure that errors coming from the
  remote watcher are caught by the synchronization process which will in turn
  alert you and stop itself and both local and remote watchers.

See also known issues.

Happy syncing!