Secret detection no run on tag

changelogs/unreleased/secret-detection-no-run-on-tag.yml

+---
+title: Skip secret_detection on tags
+merge_request: 51129
+author:
+type: changed

lib/gitlab/ci/templates/Security/Secret-Detection.gitlab-ci.yml

@@ -37,6 +37,7 @@ secret_detection:
       when: never
     - if: $CI_COMMIT_BRANCH && $CI_COMMIT_BRANCH != $CI_DEFAULT_BRANCH
   script:
+    - if [[ $CI_COMMIT_TAG ]]; echo "Skipping Secret Detection for tags. No code changes have occurred."; then exit 0; fi
     - git fetch origin $CI_DEFAULT_BRANCH $CI_COMMIT_REF_NAME
     - git log --left-right --cherry-pick --pretty=format:"%H" refs/remotes/origin/$CI_DEFAULT_BRANCH...refs/remotes/origin/$CI_COMMIT_REF_NAME > "$CI_COMMIT_SHA"_commit_list.txt
     - export SECRET_DETECTION_COMMITS_FILE="$CI_COMMIT_SHA"_commit_list.txt