Override `intl` in example

Running "flutter pub get" in example...
Resolving dependencies... (1.0s)
Because every version of flutter_quill from path depends on i18n_extension ^7.0.0 and no versions of i18n_extension match >7.0.0 <8.0.0, every version of flutter_quill from path
  requires i18n_extension 7.0.0.
And because i18n_extension 7.0.0 depends on intl ^0.18.0 and math_keyboard 0.1.8 depends on intl ^0.17.0, flutter_quill from path is incompatible with math_keyboard 0.1.8.
Because every version of flutter_quill_extensions from path depends on math_keyboard ^0.1.8 and no versions of math_keyboard match >0.1.8 <0.2.0, every version of
  flutter_quill_extensions from path requires math_keyboard 0.1.8.
Thus, flutter_quill from path is incompatible with flutter_quill_extensions from path.
So, because app depends on both flutter_quill_extensions from path and flutter_quill from path, version solving failed.
pub get failed

example/pubspec.yaml

@@ -40,6 +40,8 @@ dependency_overrides:
   flutter_quill:
     path: ../
 
+  intl: ^0.18.0
+
 dev_dependencies:
   flutter_test:
     sdk: flutter