We use semantic versioning (see http://semver.org).
- Change the file VERSION.txt with the new version number.
- Create a plain text file ../release_notes/{VERSION}, where {VERSION} is the same version number chosen in the previous step.
Commit and push your changes.
After Gitlab CI for your commit finishes, click on the button ▶ and "create-release" for the correspondent pipeline.
After that, you'll have a new release in the Releases page.
Simple like that :-)