Bump firebase_core and firebase_crashlytics in /game_template

Bumps [firebase_core](https://github.com/firebase/flutterfire/tree/master/packages/firebase_core) and [firebase_crashlytics](https://github.com/firebase/flutterfire/tree/master/packages/firebase_crashlytics). These dependencies needed to be updated together.

Updates `firebase_core` from 2.32.0 to 3.0.0
- [Release notes](https://github.com/firebase/flutterfire/releases)
- [Changelog](https://github.com/firebase/flutterfire/blob/master/CHANGELOG.md)
- [Commits](https://github.com/firebase/flutterfire/commits/firebase_core-v3.0.0/packages/firebase_core)

Updates `firebase_crashlytics` from 3.5.7 to 4.0.0
- [Release notes](https://github.com/firebase/flutterfire/releases)
- [Changelog](https://github.com/firebase/flutterfire/blob/master/CHANGELOG.md)
- [Commits](https://github.com/firebase/flutterfire/commits/firebase_crashlytics-v4.0.0/packages/firebase_crashlytics)

---
updated-dependencies:
- dependency-name: firebase_core
  dependency-type: direct:production
  update-type: version-update:semver-major
- dependency-name: firebase_crashlytics
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

game_template/pubspec.yaml

@@ -23,8 +23,8 @@ dependencies:
   # If you don't need one of the following dependencies,
   # delete the relevant line below, and get rid of any Dart code
   # that references the dependency.
-  firebase_core: ^2.1.1  # Needed for Crashlytics below
-  firebase_crashlytics: ^3.4.16  # Error reporting
+  firebase_core: ^3.0.0  # Needed for Crashlytics below
+  firebase_crashlytics: ^4.0.0  # Error reporting
   games_services: ^4.0.0  # Achievements and leaderboards
   google_mobile_ads: ^5.0.0  # Ads
   in_app_purchase: ^3.0.1  # In-app purchases