Swift Package Manager adoption

[progressify]

Hi 👋

A few days ago I updated to the latest Flutter version, and it automatically migrated my projects to SPM support.
Now I receive this warning when I run my build on iOS Simulator.

flutter run

The following plugins do not support Swift Package Manager for ios:
  - brother_printer
This will become an error in a future version of Flutter. Please contact the plugin maintainers to request Swift Package Manager adoption.