fix(firebase_core): Update google_services_gradle_plugin_version in pubspec

[frederikstonge]

Description

Update firebase_core pubspec google_services_gradle_plugin_version to match cli version

https://github.com/invertase/flutterfire_cli/blob/main/packages/flutterfire_cli/lib/src/firebase/firebase_android_writes.dart#L35

There's a TODO to read the version from firebase_core pubspec.

I did not update the version of the package as this has no effect on anything as we speak.

Checklist

Before you create this PR confirm that it meets all requirements listed below by checking the relevant checkboxes ([x]).
This will ensure a smooth and quick review process. Updating the pubspec.yaml and changelogs is not required.

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• My PR includes unit or integration tests for all changed/updated/fixed behaviors (See Contributor Guide).
• All existing and new tests are passing.
• I updated/added relevant documentation (doc comments with ///).
• The analyzer (melos run analyze) does not report any problems on my PR.
• I read and followed the Flutter Style Guide.
• I signed the CLA.
• I am willing to follow-up on review comments in a timely manner.

Breaking Change

Does your PR require plugin users to manually update their apps to accommodate your change?

• Yes, this is a breaking change.
• No, this is not a breaking change.