feat: test deploy stage

Signed-off-by: sebastien.heurtematte <sebastien.heurtematte@eclipse-foundation.org>

.gitlab-ci.yml

@@ -242,6 +242,7 @@ build-docs:
           </manifest>
           __EOM__
     # Or when things land.
+    - if: '$CI_PIPELINE_SOURCE == "merge_request_event"'
     - if: '$CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH'
 
 deploy:
@@ -274,4 +275,5 @@ deploy:
         echo "Nothing new to commit.";
       fi
   rules:
+    - if: '$CI_PIPELINE_SOURCE == "merge_request_event"'
     - if: '$CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH'