Bumping firebase-admin and firebase-functions dependencies to get support for GCP WIF

[andrewmbenton]

A longstanding issue prevented the firebase-admin node library from supporting GCP's Workload Identity Federation. That issue is now resolved as of their v13 release.

I'm hoping to get that functionality via firebase-tools but would need to bump the firebase-functions dependency in this repo as well, which it looks like may have a major impact on testing.

Anyway I am hoping to start a discussion here to determine the feasibility of bumping these two dependencies.