build(deps): bump ffigen from 19.1.0 to 20.0.0 (#140)

Bumps [ffigen](https://github.com/dart-lang/native/tree/main/pkgs) from 19.1.0 to 20.0.0.
- [Release notes](https://github.com/dart-lang/native/releases)
- [Commits](https://github.com/dart-lang/native/commits/ffigen-v20.0.0/pkgs)

---
updated-dependencies:
- dependency-name: ffigen
  dependency-version: 20.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

pubspec.lock

@@ -406,10 +406,10 @@ packages:
     dependency: "direct dev"
     description:
       name: ffigen
-      sha256: "2bd9a420ca42cb5ce8cff5d80f88547b547a042ae26807704b1698714e4464a2"
+      sha256: c880c7cda18808b10304ecbd3e3867b29a8da0d58fd2d03080829e3b65bc567c
       url: "https://pub.dev"
     source: hosted
-    version: "19.1.0"
+    version: "20.0.0"
   file:
     dependency: "direct main"
     description: