update sequelize version

Author: swarthy

package.json

@@ -24,7 +24,7 @@
   "dependencies": {
     "joi": "^10.1.0",
     "lodash": "^4.17.3",
-    "sequelize": "^3.28.0",
+    "sequelize": "^4.3.1",
     "snyk": "^1.22.1",
     "trailpack-datastore": "^2.0.0",
     "trails-service": "^2.0.0"