add mkdocstrings, update packages

Dockerfile

@@ -5,7 +5,12 @@ RUN set -ex \
     && apk add --no-cache git python3 libxml2 libxslt\
     && python3 -m ensurepip \
     && pip3 install --upgrade pip \
-    && pip3 install lxml==4.6.2 mkdocs-material==7.1.1 mkdocs-macros-plugin==0.5.0 mkdocs-mermaid2-plugin==0.5.1\
+    && pip3 install \
+    lxml==4.6.2 \
+    mkdocs-material==7.3.3 \
+    mkdocs-macros-plugin==0.6.0 \
+    mkdocs-mermaid2-plugin==0.5.2 \
+    mkdocstrings==0.16.2 \
     && apk del .build-deps
 
 WORKDIR /docs