The main code base is kept bug-free and clean by using branches for development, creating pull requests to merge new code, and tracking changes made in the pull request through a well-designed comparison page. The app's versions are handled easily by using git tags, which can trigger new builds when merged into the master branch. A release workflow can be created automatically with the help of the Generate Changelog step, which collects commit messages since the last tag event and exports them as an environment variable or a file called CHANGELOG.md. The GitHub Release step is used to create a release with the changelog, and the app's version can be deployed to the app stores by tagging a code state and triggering a build. A sample workflow is provided for reference.