Latest versions on Pypi are an incompatible combination

Hi all.

Doing a pip install -U swh.model swh.scanner results in installing swh.model==2.0.0 and swh.scanner==0.3.0 (among others), which are not compatible. Going back to swh.model==0.11.0 makes scanner work again.

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Migrated from T3101 (view on Phabricator)