Patch node-fetch security vulnerability

There is a known denial of service vulnerability in the node fetch library. This vulnerability was fixed in 2.6.1. Bumping this version should fix this downstream vulnerability.

Author: bradcypert

packages/firestore/package.json

@@ -67,7 +67,7 @@
     "@firebase/webchannel-wrapper": "0.3.0",
     "@grpc/grpc-js": "^1.0.0",
     "@grpc/proto-loader": "^0.5.0",
-    "node-fetch": "2.6.0",
+    "node-fetch": "2.6.1",
     "tslib": "^1.11.1"
   },
   "peerDependencies": {