Bumps [scikit-learn](https://github.com/scikit-learn/scikit-learn) from 0.22.1 to 0.23.1.
- [Release notes](https://github.com/scikit-learn/scikit-learn/releases)
- [Commits](https://github.com/scikit-learn/scikit-learn/compare/0.22.1...0.23.1)