fix: remove commented out security incident code, replace with warning

.gitlab-ci.yml

 default:
   before_script:
     - set -e
-    # env -0 | sort -z | tr '\0' '\n': Sort env output alphabetically, keeping multiline variables intact
-    # egrep: Remove sensitive information from the output of env
-    #- env -0 | sort -z | tr '\0' '\n' | egrep -ve '^(DOCKER_AUTH_CONFIG|GOOGLE_APPLICATION_CREDENTIALS)=.*'
+    # DANGER don't use `set -x` or print the environment via e.g. `env` in pipeline runs, this might leak credentials (has leaked them)
   tags:
     - 1cpu-4gb
   image: 'europe-north1-docker.pkg.dev/holi-shared/docker/holi-docker/holi-k6-builder'