Publish DocC to GitHub Pages with GitHub Actions

A step-by-step guide to automating DocC documentation publishing for Swift packages using GitHub Actions and GitHub Pages. Covers the GitHub Pages configuration, a DocC build workflow YAML that runs on macOS with Xcode, a multi-platform build and test workflow, and a Fastlane version bump script. Replaces a tedious manual process of generating docs and pushing to a gh-pages branch with a fully automated pipeline triggered on every push to main.