Bump sequelize from 3.35.1 to 6.29.0

Bumps [sequelize](https://github.com/sequelize/sequelize) from 3.35.1 to 6.29.0.
- [Release notes](https://github.com/sequelize/sequelize/releases)
- [Commits](sequelize/sequelize@v3.35.1...v6.29.0)

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

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

Author: dependabot[bot]

package-lock.json

@@ -83,7 +83,7 @@
     "request-promise": "^4.2.0",
     "rxjs": "^5.1.0",
     "sendgrid": "^5.2.3",
-    "sequelize": "^6.1.0",
+    "sequelize": "^6.29.0",
     "sequelize-cli": "^6.6.0",
     "sequelize-heroku": "^1.0.0",
     "stripe": "^5.8.0",