Bump ffigen from 11.0.0 to 12.0.0 in /packages/etebase

Bumps [ffigen](https://github.com/dart-lang/native/tree/main/pkgs) from 11.0.0 to 12.0.0.
- [Release notes](https://github.com/dart-lang/native/releases)
- [Commits](https://github.com/dart-lang/native/commits/HEAD/pkgs)

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

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

packages/etebase/pubspec.yaml

@@ -28,7 +28,7 @@ dev_dependencies:
   custom_lint: ^0.6.2
   dart_pre_commit: ^5.3.0
   dart_test_tools: ^5.6.2
-  ffigen: ^11.0.0
+  ffigen: ">=11.0.0 <13.0.0"
   freezed: ^2.4.7
   mocktail: ^1.0.3
   source_gen: ^1.5.0