Setup a Flutter CI/CD with GitLab CI
https://medium.com/kinandcartacreated/setup-a-flutter-ci-cd-with-gitlab-ci-part-1-8d40b7a3b3dc

OR


Automate Your Flutter Workflow Using GitLab CI/CD and Fastlane
https://medium.com/appditto/automate-your-flutter-workflow-using-gitlab-ci-cd-and-fastlane-5872e758165a