tox
(mypy complains but i don't see why immediately)
```
swh/loader/git/loader.py:125: error: Argument "config" to "__init__" of "BaseLoader" has incompatible type "Optional[Dict[str, Any]]"; expected "Dict[str, Any]"
swh/loader/git/from_disk.py:45: error: Argument "config" to "__init__" of "BaseLoader" has incompatible type "Optional[Dict[str, Any]]"; expected "Dict[str, Any]"
```