fix docs build (actually) (#359)

.github/workflows/docs.yml

@@ -38,7 +38,7 @@ jobs:
           cd docs/source
           cat tutorials_header.rst > tutorials.rst
           echo "" >> tutorials.rst
-          jupyter nbconvert --to rst ../../notebooks/00-intro.ipynb --FilesWriter.build_directory="./"
+          poetry run jupyter nbconvert --to rst ../../notebooks/00-intro.ipynb --FilesWriter.build_directory="./"
           cat 00-intro.rst >> tutorials.rst
           echo "" >> tutorials.rst
           cat tutorials_footer.rst >> tutorials.rst