build(deps): bump sequelize from 4.22.12 to 5.15.1

Bumps [sequelize](https://github.com/sequelize/sequelize) from 4.22.12 to 5.15.1.
- [Release notes](https://github.com/sequelize/sequelize/releases)
- [Commits](sequelize/sequelize@v4.22.12...v5.15.1)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

package-lock.json

@@ -89,7 +89,7 @@
     "pg": "^7.4.3",
     "pluralize": "^4.0.0",
     "remove-accents": "^0.4.2",
-    "sequelize": "^4.22.12",
+    "sequelize": "^5.15.1",
     "tmp": "0.0.33",
     "uppercamelcase": "^3.0.0",
     "winston": "^2.3.1",