Update flutter version of example

[lucribas]

Problem: The example app is incompatible with the current version of flutter (>2.10).
Solution: Recreated the example app project with "flutter create" cli and updated files.

[escamoteur]

Hi, wouldn't it have been enough to just update the pubspec.yaml?

[lucribas]

Hi, wouldn't it have been enough to just update the pubspec.yaml?

Hi, I tried to change just the pubspec.yaml but unfortunately it is not enough as there are many things that need to be changed inside the ios and android folders. (https://github.com/flutter/flutter/wiki/Upgrading-pre-1.12-Android-projects)

I found it much simpler to re-create the project with a newer version of 'flutter create'. But I understand that the PR got too big as it impacted a lot of files.

Maybe we'd better try another way.

[escamoteur]

I know that it's been a long time, but I had to make a longer break due to health issues.
I know updated all platform projects in the example project