Update dependency @types/sequelize to v4.28.15

Author: renovate[bot]

nestjs-sequelize-apis/package-lock.json

@@ -71,7 +71,7 @@
     "@types/node": "11.13.4",
     "@types/passport-jwt": "3.0.3",
     "@types/passport-local": "1.0.33",
-    "@types/sequelize": "4.28.8",
+    "@types/sequelize": "4.28.15",
     "@types/supertest": "2.0.7",
     "jest": "24.7.1",
     "prettier": "1.17.0",