⬆️ bump traitlets from 5.9.0 to 5.12.0

Bumps [traitlets](https://github.com/ipython/traitlets) from 5.9.0 to 5.12.0.
- [Release notes](https://github.com/ipython/traitlets/releases)
- [Changelog](https://github.com/ipython/traitlets/blob/main/CHANGELOG.md)
- [Commits](ipython/traitlets@v5.9.0...v5.12.0)

---
updated-dependencies:
- dependency-name: traitlets
  dependency-type: indirect
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>