Update traitlets requirement from ~=5.5.0 to ~=5.6.0

Updates the requirements on [traitlets](https://github.com/ipython/traitlets) to permit the latest version.
- [Release notes](https://github.com/ipython/traitlets/releases)
- [Changelog](https://github.com/ipython/traitlets/blob/main/CHANGELOG.md)
- [Commits](ipython/traitlets@5.5.0...v5.6.0)

---
updated-dependencies:
- dependency-name: traitlets
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

requirements.txt

@@ -153,7 +153,7 @@ tomli~=2.0.1
 tornado~=6.2
 towncrier~=22.8.0
 tqdm~=4.64.1
-traitlets~=5.5.0
+traitlets~=5.6.0
 types-requests~=2.28.11
 types-setuptools~=65.6.0
 types-tabulate~=0.9.0