How can I keep API documentation synchronized with code changes?

I'm looking for a practical way to keep API documentation synchronized with a Git-based codebase.

When API endpoints, parameters, or response structures change, the documentation can easily become outdated. I'm interested in workflows where documentation can be regenerated or updated automatically as part of the development/CI process.

Has anyone implemented a GitHub Actions or CI/CD workflow that detects relevant code changes and automatically rebuilds and publishes the API documentation?

We're working on similar documentation automation workflows at Codocly: https://codocly.in