fix: upgrade sequelize from 6.6.2 to 6.9.0

Snyk has created this PR to upgrade sequelize from 6.6.2 to 6.9.0.

See this package in npm:
https://www.npmjs.com/package/sequelize

See this project in Snyk:
https://app.snyk.io/org/jswheeler/project/5b9ad877-8370-4412-b15b-776fef739612?utm_source=github&utm_medium=referral&page=upgrade-pr

package.json

@@ -21,7 +21,7 @@
     "pg": "^8.5.1",
     "pg-hstore": "^2.3.3",
     "pgtools": "^0.3.0",
-    "sequelize": "^6.3.5",
+    "sequelize": "^6.9.0",
     "tc-bus-api-wrapper": "github:topcoder-platform/tc-bus-api-wrapper",
     "tc-core-library-js": "appirio-tech/tc-core-library-js.git#v2.6",
     "winston": "^3.2.1"