Flutter docker image

Alpine Linux images for Flutter & Dart with helpful utils and web build support.
Symlinks to dart, flutter in the folder: /opt/flutter
Rolling release update strategy every Monday.

Env

• FLUTTER_ROOT = "/opt/flutter"
• PUB_CACHE = "/var/tmp/.pub_cache"
• ANDROID_HOME = "/opt/android"

Using image as a non-flutter user

Due to git bug⁠ it is no longer possible to execute flutter commands unless you're a flutter user as underlying installation /opt/flutter is owned by this user. Either add an exception (git config --global --add safe.directory /opt/flutter) or perform all image build steps relying on flutter as the flutter user