If it's ok, I would spend the day enabling linter rules so that the
codebase is more compliant with [Effective Dart](https://dart.dev/guides/language/effective-dart)
and thus more readable for new developers.
* Upgrade upgradable packages
* Apply default null-safety migrations
* Remove hashnode as a dependency and localize its functionality to the package.
Maintenance was done long time ago hence no need to wait for the update
* Localize ui package to reduce maintenance burdens
* Replace universal html with dart:html
* Remove unnecessary checks
* Fix formatting
* Migrate app to null safety
* Enable methods to be nullable
* Fix non-nullable issue with node methods
* Cast as Node
* Use universal html
* Use universal html package to bring in the ImageElement class
* Remove unused imports
* Fix imports on the editor file
* Add key to quill editor
* Remove final from the GlobalKey
* Remove final on GlobalKey
* Remove custom util implementation in favor of quiver
* Fix issue with null on token attrivute
* Remove final hashcode that is replaced by quiver functionality
* Fix merge request
* Fix hit test position in text_line.dart
* Fix null safety errors on text_selection.dart
* Fix sound null safe errors in toolbar.dart
* Import null safe file picker
Development on the quiver_* subpackages has been discontinued in favour
of the main quiver package at https://github.com/google/quiver-dart. The
code itself is identical, but is more actively maintained.
Updated the dependency on the tuple package to 2.0.0, since it also
depends on quiver 3.0.0. Both packages has been migrated to null-safety
at those versions.
Till Friebe
Miller Adulu
Chris Bracken
Xin Yao