build(deps): bump ipykernel from 6.26.0 to 6.28.0

Bumps [ipykernel](https://github.com/ipython/ipykernel) from 6.26.0 to 6.28.0.
- [Release notes](https://github.com/ipython/ipykernel/releases)
- [Changelog](https://github.com/ipython/ipykernel/blob/main/CHANGELOG.md)
- [Commits](ipython/ipykernel@v6.26.0...v6.28.0)

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

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

requirements.txt

@@ -1,4 +1,4 @@
-ipykernel==6.26.0
+ipykernel==6.28.0
 jupyter_client==8.6.0
 pytest==7.4.2
 python-dotenv==1.0.0