Automatically assign Code Owners as reviewers

<!-- categories: Code Review Workflow -->

Previously, you needed to select reviewers for each merge request manually, even when a CODEOWNERS file already defined who should review each file.

You can now configure a project to assign Code Owners as reviewers automatically. GitLab assigns every Code Owner that matches the changed files. This happens when a merge request is created in a ready state, or when a draft is marked ready. If you already assigned a reviewer, GitLab skips automatic assignment and keeps your choice.

To turn on automatic reviewer assignment, go to Settings > Merge requests > Automatic reviewer assignment and select Automatically assign all code owners as reviewers.