Bump node-fetch from 2.6.1 to 2.6.7 in /functions (#825)

Bumps [node-fetch](https://github.com/node-fetch/node-fetch) from 2.6.1 to 2.6.7.
- [Release notes](https://github.com/node-fetch/node-fetch/releases)
- [Commits](node-fetch/node-fetch@v2.6.1...v2.6.7)

---
updated-dependencies:
- dependency-name: node-fetch
  dependency-type: direct:production
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Matt Hamrick <matthewjhamrick@gmail.com>

Author: dependabot[bot]

functions/package-lock.json

@@ -18,7 +18,7 @@
     "firebase-admin": "^8.10.0",
     "firebase-functions": "^3.13.2",
     "firebase-tools": "^9.10.0",
-    "node-fetch": "^2.6.1"
+    "node-fetch": "^2.6.7"
   },
   "devDependencies": {
     "@types/cors": "^2.8.7",