Bump pigeon in /add_to_app/books/flutter_module_books (#1120)

Bumps [pigeon](https://github.com/flutter/packages) from 3.0.2 to 3.0.3.
- [Release notes](https://github.com/flutter/packages/releases)
- [Commits](https://github.com/flutter/packages/compare/pigeon-v3.0.2...pigeon-v3.0.3)

---
updated-dependencies:
- dependency-name: pigeon
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

add_to_app/books/flutter_module_books/pubspec.lock

@@ -171,7 +171,7 @@ packages:
       name: pigeon
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "3.0.2"
+    version: "3.0.3"
   pub_semver:
     dependency: transitive
     description: