Bump flipper-redis from 0.20.3 to 0.20.4
Bump flipper-redis from 0.20.3 to 0.20.4

Bumps [flipper-redis](https://github.com/jnunemaker/flipper) from 0.20.3 to 0.20.4.
- [Release notes](https://github.com/jnunemaker/flipper/releases)
- [Changelog](https://github.com/jnunemaker/flipper/blob/master/Changelog.md)
- [Commits](https://github.com/jnunemaker/flipper/compare/v0.20.3...v0.20.4)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
indentlabs/notebook,indentlabs/notebook,indentlabs/notebook