try to pin nbconvert

nicolaskruchten · nicolaskruchten · commit adf2d980d566 · 2020-12-08T14:22:51.000-05:00
diff --git a/doc/requirements.txt b/doc/requirements.txt
@@ -30,3 +30,4 @@ kaleido
 umap-learn
 pooch
 wget
+nbconvert==5.6.1
