version 3.5 refresh use the old revision

[jneo8]

Description

If we only pass channel to the Application.refresh() without revision argument, the application only refresh the channel without change to the revision for the channel.

This happen on 3.5 release, 3.4 is working fine now. This may relate to #1067

Urgency

Casually reporting

Python-libjuju version

3.5

Juju version

controller 3.4

Reproduce / Test

await app.upgrade_charm(
    channel=channel,
    force_series=force_series,
    force_units=force_units,
    path=path,
    revision=None,
    switch=switch,
)

[gabrielcocenza]

Is this fixed with the #1067 merged?