fix readthedocs.yaml for mkdocs

Author: pcahan1

.readthedocs.yaml

@@ -6,7 +6,7 @@ build:
     python: "3"
   jobs:
     pre_install:
-      - pip install mkdocs-material mkdocstrings mkdocs-jupyter
+      - pip install mkdocs-material mkdocstrings==0.27.0 mkdocs-jupyter mkdocstrings-python mkdocs-material-extensions
 
 mkdocs:
   configuration: mkdocs.yml