Bump readthedocs-sphinx-search from 0.2.0 to 0.3.1 (#920)

Bump readthedocs-sphinx-search from 0.2.0 to 0.3.1 (#920)

Bumps [readthedocs-sphinx-search](https://github.com/readthedocs/readthedocs-sphinx-search) from 0.2.0 to 0.3.1.
- [Release notes](https://github.com/readthedocs/readthedocs-sphinx-search/releases)
- [Changelog](https://github.com/readthedocs/readthedocs-sphinx-search/blob/main/CHANGELOG.rst)
- [Commits](https://github.com/readthedocs/readthedocs-sphinx-search/commits)

---
updated-dependencies:
- dependency-name: readthedocs-sphinx-search
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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