logilab-common #88981 Add argments to shellutils.ProgressBar.update [validation pending]

Add arguments to update the progressbar to more than 1 step. It shall also be useful to allow to specify an absolute value.

This will allow to write something like:

downloader = Downloader()
progress_bar = ProgressBar(download.total)
while not downloader.finished:
    downloader.fetch_more()
    progress_bar.update(downloader.status, absolute=True)
prioritynormal
typeenhancement
done in0.58.0
load0.500
load left0.000
closed by#a3d03836ead9 [shellutil] add argument to ``ProgressBar.update`` to tune cursor progression (closes #88981)