Ubuntu agent fails

[eino-makitalo]

##[section]Starting: Install Flutter SDK
==============================================================================
Task         : Install Flutter SDK
Description  : Installs the Flutter SDK and add it to your `PATH` environment. You can then run `flutter` commands in succeeding tasks using the command line.
Version      : 0.1.9
Author       : contrix09
Help         : Go to http://flutter.io for more information.
==============================================================================
Downloading latest sdk version '1.9.1+hotfix.2-stable' from channel 'stable' from https://storage.googleapis.com/flutter_infra/releases/stable/linux/flutter_linux_v1.9.1+hotfix.2-stable.zip
Downloading: https://storage.googleapis.com/flutter_infra/releases/stable/linux/flutter_linux_v1.9.1+hotfix.2-stable.zip
##[error]Unexpected HTTP response: 404
##[section]Finishing: Install Flutter SDK

[dustincatap]

@eino-makitalo fixed.
Moved this repo to https://github.com/cross-solutions/install-flutter-sdk