ci: Fix pull rate limit errors

Pull the container from a source without a rate limit

Suggested by Daniel Stone <daniels@collabora.com>

Signed-off-by: Derek Foreman <derek.foreman@collabora.com>

.gitlab-ci.yml

@@ -137,6 +137,9 @@ build-no-gl:
   extends: .build-and-test
 
 docs-and-coverage:
+  extends:
+    - .debian
+    - .fdo.distribution-image@debian
   stage: pages
   timeout: 5m
   script: