ci: Upgrade python-dbusmock version
This is needed for running GNOME Shell, as the older version has an incorrect PowerProfiles property type.
Includes https://github.com/martinpitt/python-dbusmock/pull/167.
This is needed for running GNOME Shell, as the older version has an incorrect PowerProfiles property type.
Includes https://github.com/martinpitt/python-dbusmock/pull/167.