gitlab-ci.yml: correct exclusion rule

.gitlab-ci.yml

@@ -55,5 +55,5 @@ apache-dev:
     - echo "Publishing to $PUBLISH_DIR"
     - sed "s/^[[:space:]]*SITEURL[[:space:]]*=.*/SITEURL = 'https:\/\/calcul-dev.math.unistra.fr\/$CI_COMMIT_REF_NAME'/" publishconf.py > publishconf-dev.py
     - pelican -s publishconf-dev.py --fatal errors
-    - rsync -av --delete --filter 'protect $PUBLISH_DIR/attachments/' output/ $PUBLISH_DIR/
+    - rsync -av --delete --exclude $PUBLISH_DIR/attachments output/ $PUBLISH_DIR/
     - rsync -av --delete content/attachments/ $PUBLISH_DIR/attachments/