Bump pytest-doctestplus from 1.1.0 to 1.2.1

Bumps [pytest-doctestplus](https://github.com/scientific-python/pytest-doctestplus) from 1.1.0 to 1.2.1.
- [Release notes](https://github.com/scientific-python/pytest-doctestplus/releases)
- [Changelog](https://github.com/scientific-python/pytest-doctestplus/blob/main/CHANGES.rst)
- [Commits](scientific-python/pytest-doctestplus@v1.1.0...v1.2.1)

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

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