Bump https-proxy-agent in /firestore/solution-deletes/functions (#100)

Bumps [https-proxy-agent](https://github.com/TooTallNate/node-https-proxy-agent) from 2.2.1 to 2.2.4.
- [Release notes](https://github.com/TooTallNate/node-https-proxy-agent/releases)
- [Commits](TooTallNate/proxy-agents@2.2.1...2.2.4)

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

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

Author: dependabot[bot]