Keybase Updater Should Have Progress Indicator

Currently on Windows, when a Keybase client update is available, a pop-up dialog box appears and gives you the option to either snooze or apply the update immediately. However, after you click "Apply", the dialog box disappears and there is no indicator that the update is in progress, even though the update **is** proceeding normally in the background (I was able to verify this by going into the temporary directory where Keybase stores the update as is it is being downloaded and saw the temporary download file was continuously getting bigger). This behavior can be very confusing to most users. Most software applications have some sort of progress indicator as they download and install an update. I would suggest adding that feature to the Keybase client updater, so users have a clear indication that an update is in progress, and a clear indication of when the update has completed successfully.

Start with the Windows Keybase client updater flow described in the issue and trace what happens after the user clicks "Apply". Check the temporary download activity while the update runs, then define completion as a visible progress indication during download and installation plus a clear successful-completion state.

Written by the indexing model from the issue text.