Bump async in /unit-test-cloud-functions/functions (#321)

Bumps  and [async](https://github.com/caolan/async). These dependencies needed to be updated together.

Updates `async` from 3.2.1 to 3.2.4
- [Release notes](https://github.com/caolan/async/releases)
- [Changelog](https://github.com/caolan/async/blob/master/CHANGELOG.md)
- [Commits](caolan/async@v3.2.1...v3.2.4)

Updates `async` from 2.6.3 to 3.2.4
- [Release notes](https://github.com/caolan/async/releases)
- [Changelog](https://github.com/caolan/async/blob/master/CHANGELOG.md)
- [Commits](caolan/async@v3.2.1...v3.2.4)

---
updated-dependencies:
- dependency-name: async
  dependency-type: indirect
- dependency-name: async
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]