Bump ipykernel from 6.23.1 to 6.23.3 in /docs

Bumps [ipykernel](https://github.com/ipython/ipykernel) from 6.23.1 to 6.23.3.
- [Release notes](https://github.com/ipython/ipykernel/releases)
- [Changelog](https://github.com/ipython/ipykernel/blob/main/CHANGELOG.md)
- [Commits](ipython/ipykernel@v6.23.1...v6.23.3)

---
updated-dependencies:
- dependency-name: ipykernel
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

docs/requirements.txt

@@ -4,4 +4,4 @@ sphinx-rtd-theme==1.2.1
 autodoc_pydantic==1.8.0
 sphinx-gallery==0.10.1
 nbsphinx==0.9.2
-ipykernel==6.23.1
+ipykernel==6.23.3