docs: add notebook_shim dep

Author: echarles

docs/environment.yml

@@ -1,4 +1,4 @@
-name: notebook_docs
+name: nbclassic_docs
 channels:
   - conda-forge
 dependencies:
@@ -20,3 +20,4 @@ dependencies:
   - sphinxcontrib_github_alt
   - ipython_genutils
   - jupyter_server>=1.8
+  - notebook_shim>=0.1.0