How to automatically create a new MR on GitLab with GitLab CI

What this post added

Introduced a GitLab CI script that automatically creates a Merge Request (MR) for a new branch. The script checks if an open MR already exists for the source branch; if not, it creates one, assigns it to the committer (using GITLAB_USER_ID), sets the target branch to the default branch, and marks the title with 'WIP:'. It also configures the MR to automatically remove the source branch upon merging.