ci(docs): fix the doc publishing job (#261)

* ci(docs): fix the doc publishing job

* ci(docs): put dependency in setup.cfg

Author: deepcharles

setup.cfg

@@ -57,7 +57,7 @@ docs =
     mkdocs-macros-plugin
     mkdocs-material
     mkdocs-section-index
-    mkdocstrings
+    mkdocstrings[python]>=0.18 # https://mkdocstrings.github.io/handlers/overview/#about-the-python-handlers
     mknotebooks
     pymdown-extensions
     nltk