Maybe unstuck CI: Try 2

.gitlab-ci.yml

-job:
-  tags:
-    - au
-
 stages:
   - build
 
 .build:
   stage: build
   image: coqorg/${CI_JOB_NAME}
+  tags: au
   before_script:
     - if [ -n "${COMPILER_EDGE}" ]; then opam switch ${COMPILER_EDGE} && eval $(opam env); fi
     - opam update -y