Bump @types/chai from 4.2.12 to 4.3.1 in /functions

Bumps [@types/chai](https://github.com/DefinitelyTyped/DefinitelyTyped/tree/HEAD/types/chai) from 4.2.12 to 4.3.1.
- [Release notes](https://github.com/DefinitelyTyped/DefinitelyTyped/releases)
- [Commits](https://github.com/DefinitelyTyped/DefinitelyTyped/commits/HEAD/types/chai)

---
updated-dependencies:
- dependency-name: "@types/chai"
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

functions/package-lock.json

@@ -24,7 +24,7 @@
     "inquirer": "^7.3.3"
   },
   "devDependencies": {
-    "@types/chai": "^4.2.12",
+    "@types/chai": "^4.3.1",
     "@types/chai-as-promised": "^7.1.3",
     "@types/mocha": "^8.0.4",
     "chai": "^4.2.0",