.gitlab-ci.yml: add dependencies to avoid downloading unneeded artifacts

.gitlab-ci.yml

@@ -47,6 +47,7 @@ get coverage:
 contributors:
   image: debian:buster
   stage: deploy
+  dependencies: []
   script:
     - apt update && apt install -y git python3-debiancontributors
     - dc-tool --mine config/debian/contributor.patch --auth-token "@$DC_TOKEN" --source ftp.debian.org --post
@@ -63,6 +64,8 @@ pages:
     - epydoc -q --html --graph all --css white -n DAK -o public/epydoc --include-log --show-imports dak dakweb
     - mv coverage public/coverage
   stage: deploy
+  dependencies:
+    - get coverage
   artifacts:
     paths:
       - public