Log Message:
py-traitlets: updated to 5.2.2

5.2.2
- Make ``traitlets.__all__`` explicit and validate in test.
- Fix ``KeyError`` in ``Application.get_default_logging_config``.

5.2.1
- logging: Don't attempt to close handlers unless they have been opened.
  Fixes ``ValueError: Unable to configure formatter 'console'`` traceback.

5.2.0
Traitlets 5.2 brings a couple of updates and changes to traitlets, and is
recommended for all users. What follows is a non-exhaustive list of changes:

- Application: add logging_config trait.
- Disambiguate the use of the term value in the example.
- Add mypy typing support.
- DOC: Add log example.
- Internal cleanup: linters, autoformatters, CI.