chore(deps): bump ffigen in the ffigen group across 1 directory

Bumps the ffigen group with 1 update in the / directory: [ffigen](https://github.com/dart-lang/native/tree/main/pkgs).


Updates `ffigen` from 9.0.1 to 21.0.0
- [Release notes](https://github.com/dart-lang/native/releases)
- [Commits](https://github.com/dart-lang/native/commits/ffigen-v21.0.0/pkgs)

---
updated-dependencies:
- dependency-name: ffigen
  dependency-version: 21.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: ffigen
...

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

Author: dependabot[bot]

pubspec.yaml

@@ -27,7 +27,7 @@ dependencies:
   device_info_plus: ^13.1.0
   drift: ^2.34.0
   drift_dev: ^2.34.0
-  ffigen: ^9.0.0
+  ffigen: ^21.0.0
   file: ^7.0.1
   flutter_plugin_android_lifecycle: ^2.0.9
   graphs: ^2.1.0