Bump joblib from 1.1.0 to 1.2.0 in /examples/iris

Bumps [joblib](https://github.com/joblib/joblib) from 1.1.0 to 1.2.0.
- [Release notes](https://github.com/joblib/joblib/releases)
- [Changelog](https://github.com/joblib/joblib/blob/master/CHANGES.rst)
- [Commits](joblib/joblib@1.1.0...1.2.0)

---
updated-dependencies:
- dependency-name: joblib
  dependency-type: indirect
...

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