fix(deps): bump jest-diff from 26.3.0 to 26.4.0

Bumps [jest-diff](https://github.com/facebook/jest/tree/HEAD/packages/jest-diff) from 26.3.0 to 26.4.0.
- [Release notes](https://github.com/facebook/jest/releases)
- [Changelog](https://github.com/facebook/jest/blob/master/CHANGELOG.md)
- [Commits](https://github.com/facebook/jest/commits/v26.4.0/packages/jest-diff)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>