Update .gitlab-ci.yml file

.gitlab-ci.yml

@@ -10,6 +10,8 @@ pages:
     - mkdir -p cas/_build/.jupyter_cache/
     - ln -s src cas/src
     - ln -s data cas/data
+    - ls -la cas
+    - ls -la cas/src
     - jupyter-book build cas
     - rm -rf public/pycas
     - cp -r  cas/_build/html public/pycas