output format specified

.github/workflows/ci.yaml

@@ -35,7 +35,7 @@ jobs:
         run: |
           pip install jupyter
           for file in examples/*.ipynb; do
-            jupyter nbconvert --execute --ExecutePreprocessor.timeout=300 "$file"
+            jupyter nbconvert --to html --execute --ExecutePreprocessor.timeout=300 "$file"
           done
 
       - name: Docstring Lint