swh-apps: Fix swh-loader-bzr application image build
It's currently broken [1] on the breezy deps [2].
[2]
...
11:21:45 ModuleNotFoundError: No module named 'configobj'
11:21:45 [end of output]
...
11:21:48 Failed to build breezy
11:21:48 ERROR: Could not build wheels for breezy, which is required to install pyproject.toml-based projects
[1] https://jenkins.softwareheritage.org/job/swh-apps/job/build-docker-image/72/console