flutter-sudo master tag has flutter stable channel

[AliceGrey]

The flutter-sudo images that are tagged with master are being built with the stable flutter channel and not the master channel. https://hub.docker.com/layers/fischerscode/flutter-sudo/master/images/sha256-87be43844c2a0a609d79b0e9c56cb0f7a413a5e17be03246e22d53411eef39f4?context=explore

I think this may be the culprit

DockerFlutter/Dockerfile.sudo

Line 1 in 2175edf

ARG flutterTag=stable