Upgrade: Bump sequelize from 5.22.5 to 6.29.0 in /ch7/back

Bumps [sequelize](https://github.com/sequelize/sequelize) from 5.22.5 to 6.29.0.
- [Release notes](https://github.com/sequelize/sequelize/releases)
- [Commits](sequelize/sequelize@v5.22.5...v6.29.0)

---
updated-dependencies:
- dependency-name: sequelize
  dependency-type: direct:production
...

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Author: dependabot[bot]