Bump traitlets from 5.0.5 to 5.1.0
Bump traitlets from 5.0.5 to 5.1.0

Bumps [traitlets](https://github.com/ipython/traitlets) from 5.0.5 to 5.1.0.
- [Release notes](https://github.com/ipython/traitlets/releases)
- [Commits](https://github.com/ipython/traitlets/compare/5.0.5...5.1.0)

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

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@github.com>
jhamrick/nbgrader,jupyter/nbgrader,jupyter/nbgrader,jhamrick/nbgrader,jhamrick/nbgrader,jupyter/nbgrader,jhamrick/nbgrader,jupyter/nbgrader,jupyter/nbgrader