Bump ioredis from 4.17.3 to 4.19.4

Bumps [ioredis](https://github.com/luin/ioredis) from 4.17.3 to 4.19.4.
- [Release notes](https://github.com/luin/ioredis/releases)
- [Changelog](https://github.com/luin/ioredis/blob/master/Changelog.md)
- [Commits](redis/ioredis@v4.17.3...v4.19.4)

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Author: dependabot[bot]