tox packaging job fails in CI

Personne n'a encore pris cette issue.

E.g. as in https://travis-ci.org/github/matrix-org/python-signedjson/jobs/770347173

```
$ tox
GLOB sdist-make: /home/travis/build/matrix-org/python-signedjson/setup.py
packaging create: /home/travis/build/matrix-org/python-signedjson/.tox/packaging
packaging installdeps: check-manifest
packaging inst: /home/travis/build/matrix-org/python-signedjson/.tox/.tmp/package/1/signedjson-1.1.2.dev6+gde64b47.zip
packaging installed: canonicaljson==1.1.4,cffi==1.14.0,check-manifest==0.41,frozendict==1.2,importlib-metadata==1.6.0,pep517==0.8.2,pycparser==2.20,PyNaCl==1.3.0,signedjson==1.1.2.dev6+gde64b47,simplejson==3.17.0,six==1.14.0,toml==0.10.0,typing-extensions==3.7.4.2,unpaddedbase64==1.1.0,zipp==3.1.0
packaging run-test-pre: PYTHONHASHSEED='2381353217'
packaging run-test: commands[0] | check-manifest
lists of files in version control and sdist do not match!
missing from sdist:
CHANGELOG.md
RELEASING.md
changelog.d
pyproject.toml
suggested MANIFEST.in rules:
include *.md
include *.toml
ERROR: InvocationError for command /home/travis/build/matrix-org/python-signedjson/.tox/packaging/bin/check-manifest (exited with code 1)
___________________________________ summary ____________________________________
ERROR: packaging: commands failed
The command "tox" exited with 1.
Done. Your build exited with 1.
```

Commencez par exécuter tox et inspecter setup.py, la configuration de la tâche de packaging et la sortie de check-manifest. Confirmez pourquoi CHANGELOG.md, RELEASING.md, changelog.d et pyproject.toml sont absents de la distribution source, puis vérifiez que la tâche de packaging s’exécute correctement avec tous les fichiers requis inclus.

Rédigé par le modèle d'indexation à partir du texte de l'issue.