[keyserver] Bump firebase-admin to 10.1.0

Summary:
Downstream dependencies have issues surfaced by yarn audit

Checked the 10.0.2 and 10.1.0 release notes and found no evidence of breaking changes: https://github.com/firebase/firebase-admin-node/releases

Test Plan: CI

Reviewers: def-au1t, palys-swm, ashoat

Reviewed By: ashoat

Subscribers: Adrian, karol-bisztyga, yayabosh

Differential Revision: https://phabricator.ashoat.com/D3855