Build(deps): Bump nbconvert from 7.13.0 to 7.16.4 in /requirements

Bumps [nbconvert](https://github.com/jupyter/nbconvert) from 7.13.0 to 7.16.4.
- [Release notes](https://github.com/jupyter/nbconvert/releases)
- [Changelog](https://github.com/jupyter/nbconvert/blob/main/CHANGELOG.md)
- [Commits](jupyter/nbconvert@v7.13.0...v7.16.4)

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

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

Author: dependabot[bot]

requirements/requirements_doc.txt

@@ -35,4 +35,4 @@ sphinx-notfound-page==1.0.0
 sphinx_design==0.6.0
 sphinxcontrib-websupport==1.2.7
 jupytext==1.16.1
-nbconvert==7.13.0
+nbconvert==7.16.4