Add to lists of open source apps

[maksymilian-majer]

• [x] https://github.com/tortuvshin/open-source-flutter-apps
• [ ] https://www.dunebook.com/amazing-opensource-games-built-using-flutter/
• [ ] Awesome flutter – example PR 1 example PR 2

[maksymilian-majer]

The PR to open source apps repo has been created: https://github.com/tortuvshin/open-source-flutter-apps/pull/35

[Alsma201]

Yes