fix: upgrade multiple dependencies with Snyk

Snyk has created this PR to upgrade:
  - tslib from 2.4.1 to 2.6.3.
    See this package in npm: https://www.npmjs.com/package/tslib
  - firebase from 9.14.0 to 9.23.0.
    See this package in npm: https://www.npmjs.com/package/firebase
  - @angular/fire from 7.5.0 to 7.6.1.
    See this package in npm: https://www.npmjs.com/package/@angular/fire
  - angular-cli-ghpages from 1.0.5 to 1.0.7.
    See this package in npm: https://www.npmjs.com/package/angular-cli-ghpages
  - date-fns from 2.29.3 to 2.30.0.
    See this package in npm: https://www.npmjs.com/package/date-fns
  - firebase-admin from 11.3.0 to 11.11.1.
    See this package in npm: https://www.npmjs.com/package/firebase-admin
  - rxjs from 7.5.0 to 7.8.1.
    See this package in npm: https://www.npmjs.com/package/rxjs
  - zone.js from 0.11.8 to 0.15.0.
    See this package in npm: https://www.npmjs.com/package/zone.js

See this project in Snyk:
https://app.snyk.io/org/jcharra/project/c377aae5-689c-433c-96a7-b9f970b5b646?utm_source=github&utm_medium=referral&page=upgrade-pr