[pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

Author: pre-commit-ci[bot]

paper/paper.bib

@@ -18,4 +18,4 @@ @unpublished{interactive_Jupyter_widgets
 title = {ipywidgets, a GitHub repository},
 year = {2015},
 note = {Retrieved from https://github.com/jupyter-widgets/ipywidgets}
-}
+}