Bump moment from 2.24.0 to 2.29.2 in /functions

Bumps [moment](https://github.com/moment/moment) from 2.24.0 to 2.29.2.
- [Release notes](https://github.com/moment/moment/releases)
- [Changelog](https://github.com/moment/moment/blob/develop/CHANGELOG.md)
- [Commits](moment/moment@2.24.0...2.29.2)

---
updated-dependencies:
- dependency-name: moment
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

functions/package-lock.json

@@ -18,7 +18,7 @@
     "firebase": "^6.4.2",
     "firebase-admin": "^8.0.0",
     "firebase-functions": "^3.0.0",
-    "moment": "^2.24.0"
+    "moment": "^2.29.2"
   },
   "devDependencies": {
     "tslint": "^5.12.0",