Bump firebase from 3.6.9 to 10.9.0

Bumps [firebase](https://github.com/firebase/firebase-js-sdk) from 3.6.9 to 10.9.0.
- [Release notes](https://github.com/firebase/firebase-js-sdk/releases)
- [Changelog](https://github.com/firebase/firebase-js-sdk/blob/main/CHANGELOG.md)
- [Commits](https://github.com/firebase/firebase-js-sdk/compare/rxfire@3.6.9...firebase@10.9.0)

---
updated-dependencies:
- dependency-name: firebase
  dependency-version: 10.9.0
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

package.json

@@ -23,7 +23,7 @@
     "angularfire2": "^2.0.0-beta.7",
     "bootstrap": "^4.1.3",
     "core-js": "2.4.1",
-    "firebase": "3.6.9",
+    "firebase": "10.9.0",
     "ng2-bootstrap": "^1.3.3",
     "ng2-dnd": "^2.2.2",
     "rxjs": "5.0.3",