The Jandex project relies on GitHub Actions to create a release.
By convention, use a branch named release-<x.y.z> where x.y.z is the version that is about to be released.
The PR should only contain changes to the .github/project.yml file and specifies the version to release, and the next version to set in the POM (with a trailing -SNAPSHOT).
This PR must be pushed to the smallrye/jandex repository.
Pushing it to a fork will not create a release.
Once this PR is opened, it will check that it can be used to create a release.
Once merged, GitHub Actions will update the project and perform the release to deploy the artifacts in Maven Central.
The GitHub action also creates Release Notes corresponding to the new tag.
There is more information about the release process in the Release Process wiki page.