Flutter Desktop Docker Container

Docker containers for performing Flutter desktop builds.

These docker containers incorporate or are build on cirrusci (cirruslabs).

linux-fstable-3.10.2 is flutter 3.10.2, glibc 2.31, apt installing the needed utils including npm, cucumber-html-reporter

windows-sdk30-fstable-3.10.2 is cirrusci/android-sdk:30-windowsservercore-2019 with Visual Studio 16, Flutter stable (3.10.2), and Google Root cert gtsr1 (for future proofing pub get)