tox fails because it needs a bump in swh.core requirements.
Patching locally the .tox venv (with D7880), it's all fine:
```
...
.tox/py3/lib/python3.9/site-packages/swh/lister/maven/tests/test_lister.py ............. [ 61%]
.tox/py3/lib/python3.9/site-packages/swh/lister/maven/tests/test_tasks.py ... [ 62%]
...
================================================================================================= 209 passed, 5 warnings in 72.17s (0:01:12) ==================================================================================================
```