Bump ipython from 8.18.1 to 8.21.0

Bumps [ipython](https://github.com/ipython/ipython) from 8.18.1 to 8.21.0.
- [Release notes](https://github.com/ipython/ipython/releases)
- [Commits](ipython/ipython@8.18.1...8.21.0)

---
updated-dependencies:
- dependency-name: ipython
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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