[Security] Bump sequelize from 5.12.3 to 5.21.1
[Security] Bump sequelize from 5.12.3 to 5.21.1

Bumps [sequelize](https://github.com/sequelize/sequelize) from 5.12.3 to 5.21.1. **This update includes a security fix.**
- [Release notes](https://github.com/sequelize/sequelize/releases)
- [Commits](https://github.com/sequelize/sequelize/compare/v5.12.3...v5.21.1)

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

npenin/domojs,npenin/domojs,npenin/domojs