Comment 0 for bug 1965600

Launching from command line:
> $ backintime-qt
> Traceback (most recent call last):
> File "/usr/share/backintime/qt/app.py", line 35, in <module>
> import qttools
> File "/usr/share/backintime/qt/qttools.py", line 47, in <module>
> import snapshots
> File "/usr/share/backintime/common/snapshots.py", line 34, in <module>
> import config
> File "/usr/share/backintime/common/config.py", line 32, in <module>
> import tools
> File "/usr/share/backintime/common/tools.py", line 1802, in <module>
> class OrderedSet(collections.MutableSet):
> AttributeError: module 'collections' has no attribute 'MutableSe

     affects backintime

Following https://github.com/OCA/oca-addons-repo-template/issues/80 the
attached patch solves.

Ubuntu 22.04 development version
Package: backintime-common
Version: 1.2.1-3