tox (existing tests are happy, i don't see clearly how to simulate that error in tests though so as is sounds good to me)
docker
Without this commit, this can happen:
```
swh-lister_1 | [2022-02-17 09:39:28,685: INFO/MainProcess] Task swh.lister.launchpad.tasks.IncrementalLaunchpadLister[51954eb9-5c55-467e-9091-729361ab4ef8] received
swh-lister_1 | [2022-02-17 09:45:31,974: ERROR/ForkPoolWorker-1] Task swh.lister.launchpad.tasks.IncrementalLaunchpadLister[51954eb9-5c55-467e-9091-729361ab4ef8] raised unexpected: RestfulError()
swh-lister_1 | Traceback (most recent call last):
swh-lister_1 | File "/srv/softwareheritage/venv/lib/python3.7/site-packages/celery/app/trace.py", line 450, in trace_task
swh-lister_1 | R = retval = fun(*args, **kwargs)
swh-lister_1 | File "/srv/softwareheritage/venv/lib/python3.7/site-packages/swh/scheduler/task.py", line 55, in __call__
swh-lister_1 | result = super().__call__(*args, **kwargs)
swh-lister_1 | File "/srv/softwareheritage/venv/lib/python3.7/site-packages/celery/app/trace.py", line 731, in __protected_call__
swh-lister_1 | return self.run(*args, **kwargs)
swh-lister_1 | File "/src/swh-lister/swh/lister/launchpad/tasks.py", line 27, in list_launchpad_incremental
swh-lister_1 | return lister.run().dict()
swh-lister_1 | File "/src/swh-lister/swh/lister/pattern.py", line 130, in run
swh-lister_1 | full_stats.origins += self.send_origins(origins)
swh-lister_1 | File "/src/swh-lister/swh/lister/pattern.py", line 233, in send_origins
swh-lister_1 | for batch_origins in grouper(origins, n=1000):
swh-lister_1 | File "/srv/softwareheritage/venv/lib/python3.7/site-packages/swh/core/utils.py", line 47, in grouper
swh-lister_1 | for _data in itertools.zip_longest(*args, fillvalue=stop_value):
swh-lister_1 | File "/src/swh-lister/swh/lister/launchpad/lister.py", line 149, in get_origins_from_page
swh-lister_1 | for repo in repos:
swh-lister_1 | File "/srv/softwareheritage/venv/lib/python3.7/site-packages/lazr/restfulclient/resource.py", line 819, in __iter__
swh-lister_1 | next_get = self._root._browser.get(URI(next_link))
swh-lister_1 | File "/srv/softwareheritage/venv/lib/python3.7/site-packages/lazr/restfulclient/_browser.py", line 439, in get
swh-lister_1 | response, content = self._request(url, extra_headers=headers)
swh-lister_1 | File "/srv/softwareheritage/venv/lib/python3.7/site-packages/lazr/restfulclient/_browser.py", line 429, in _request
swh-lister_1 | raise error
swh-lister_1 | lazr.restfulclient.errors.RestfulError
```