Bump jest from 25.2.4 to 25.2.6 (#301)

Bumps [jest](https://github.com/facebook/jest) from 25.2.4 to 25.2.6.
- [Release notes](https://github.com/facebook/jest/releases)
- [Changelog](https://github.com/facebook/jest/blob/master/CHANGELOG.md)
- [Commits](jestjs/jest@v25.2.4...v25.2.6)

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Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>