build(deps): bump sequelize from 6.21.2 to 6.28.2 (#638)

Bumps [sequelize](https://github.com/sequelize/sequelize) from 6.21.2 to 6.28.2.
- [Release notes](https://github.com/sequelize/sequelize/releases)
- [Commits](sequelize/sequelize@v6.21.2...v6.28.2)

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

package.json

@@ -63,7 +63,7 @@
     "pg-connection-string": "^2.5.0",
     "query-string": "^6.14.1",
     "reflect-metadata": "^0.1.13",
-    "sequelize": "^6.21.2",
+    "sequelize": "^6.28.2",
     "sequelize-typescript": "^2.1.3",
     "serialize-error": "^7.0.1",
     "slugify": "^1.6.0",