rework job rules

.gitlab/ci/cve-scan.gitlab-ci.yml

@@ -25,14 +25,10 @@ docker-image-scan:
       - "*.cve"
     expire_in: 30 days
   rules:
-    # This will ensure the job only runs on pushes to the `main` branch (not MRs or other branches)
-    - if: '$CI_COMMIT_BRANCH == "main" && $CI_PIPELINE_SOURCE == "push"'
+    # Run only when a merge request is merged into the `main` branch
+    - if: '$CI_MERGE_REQUEST_TARGET_BRANCH_NAME == "main" && $CI_PIPELINE_SOURCE == "merge_request_event" && $CI_MERGE_REQUEST_EVENT_TYPE == "merged"'
       when: always
-    # This will prevent the job from running for any branch other than `main`
-    - if: '$CI_COMMIT_BRANCH != "main"'
-      when: never
-    # This ensures that the job does not run if triggered by a merge request pipeline
-    - if: '$CI_PIPELINE_SOURCE == "merge_request_event"'
-      when: never
+    # Prevent the job from running in all other cases
+    - when: never
   tags:
     - "dind"
\ No newline at end of file