Add resolutions to fix remaining dependency vulnerabilities

Summary:
Follow-up to D99691259 (which deleted the stale yarn.lock).

Adds resolutions to quick-start/package.json to force safe versions of
exact-pinned transitive dependencies, preventing vulnerabilities from
reappearing if a new lockfile is generated:
- tough-cookie: 2.4.3 → 4.1.3 (pinned by request via ~2.4.3)
- form-data: 2.3.3 → 2.5.4 (pinned by request via ~2.3.2)
- qs: 6.5.2 → 6.14.1 (pinned by express at exact version)
- ajv: 6.7.0 → 6.14.0 (pinned by request → har-validator)

Note: request@2.88.2 itself is deprecated with no fix version available.
The node/package.json ejs vulnerability is already resolved (^3.1.10).

Reviewed By: shreeshyadav

Differential Revision: D99724725

fbshipit-source-id: ceedd104b8f4ef7df56016d69f9a6aa19830f556

Author: Vinayak Gupta

quick-start/package.json

@@ -23,5 +23,11 @@
   "keywords": [
     "messenger",
     "webhook"
-  ]
+  ],
+  "resolutions": {
+    "tough-cookie": "4.1.3",
+    "form-data": "2.5.4",
+    "qs": "6.14.1",
+    "ajv": "6.14.0"
+  }
 }