MAINT: Update .gitlab-ci.yml file, building docs only for releases

.gitlab-ci.yml

@@ -286,9 +286,9 @@ pages_prepare: &pages_prepare
   stage: deploy
   needs: []
   image: $CI_REGISTRY/caosdb/src/caosdb-pylib/testenv:latest
-#  only:
-#    refs:
-#      - /^release-.*$/i
+  only:
+    refs:
+      - /^release-.*$/i
   script:
     - echo "Deploying documentation"
     - make doc
@@ -298,6 +298,6 @@ pages_prepare: &pages_prepare
       - public
 pages:
   <<: *pages_prepare
-#  only:
-#    refs:
-#      - main
+  only:
+    refs:
+      - main