🚀 Slight updates but necessary

In this release I have done the following:

• Updated the User-Agent when downloading the Flutter SDK to be a custom one as per (Flutter SDK Per-platform Installer Requirements](https://docs.google.com/document/d/1VooN2bddQ52Z2B4qYi1Lp20PGhyYDr1AKaXwo9e7PCw/edit?usp=sharing)
• General bug fixes
• Updated all packages to the latest releases

Here is the CHANGELOG section:

Added

• Started using file_selector plugin

Changed

• User-Agent now is a custom one when downloading the Flutter SDK as per Flutter Installer requirements
• Upgraded all packages to latest possible

Fixed

• General bug fixes

Removed

• Removed file_chooser plugin