build(deps): bump intl in /modules/serverpod_chat/serverpod_chat_flutter

Bumps [intl](https://github.com/dart-lang/i18n/tree/main/pkgs) from 0.19.0 to 0.20.0.
- [Release notes](https://github.com/dart-lang/i18n/releases)
- [Commits](https://github.com/dart-lang/i18n/commits/intl-v0.20.0/pkgs)

---
updated-dependencies:
- dependency-name: intl
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

modules/serverpod_chat/serverpod_chat_flutter/pubspec.yaml

@@ -16,7 +16,7 @@ dependencies:
   flutter:
     sdk: flutter
   file_picker: ^8.0.0
-  intl: ^0.19.0
+  intl: ">=0.19.0 <0.21.0"
   url_launcher: ^6.1.10
   path: ^1.8.2
   serverpod_auth_client: 2.2.0-beta.1