fix(firebase-admin-version): Update firebase-admin to fix @google-cloud/firestore

[eliasreis54]

Hi! 👋

We found this error while we were trying to use this project:

Error: Cannot find module '@google-cloud/firestore'

We have realized that updating the firebase-admin version fixes the issue.

So we have decided to open this pull request.

[leonbeckert]

Thanks, helped a lot!

[guilleliss]

This was helpful, thanks!