git is not installed there either, but at least we have root

.gitlab-ci.yml

@@ -6,6 +6,7 @@ find-files-commit:
   stage: build
   image: debian:stable-slim
   script:
+    - apt update && apt install -yy --no-install-recommends git
     - echo "commit SHA $CI_COMMIT_SHA"
     - echo "working on files..."
     - git diff-tree --no-commit-id --name-only -r $CI_COMMIT_SHA | tee changed-files.txt