Show last sync time in addition to "Up to date"

[diklein]

Is your feature request related to a problem? Please describe.
When syncing 100-200mb files to Dropbox, sometimes it takes a few seconds and sometimes it takes a minute. If my internet speed is particularly fast at the moment, I'm not confident that Maestral already completed the upload, or is about to start uploading.

Describe the solution you'd like
I would like to see a timestamp of the last sync time in addition to "Up to date" text in the menu.

Describe alternatives you've considered
Perhaps I can hold option down when I click on the menubar icon to see additional information such as a timestamp for the last sync. Maybe the last synchronized file name could also appear in the menu for instilling even more confidence that the file was successfully uploaded.