Install as a package, duh

Dockerfile

@@ -10,6 +10,7 @@ COPY sbin/* /sbin/
 RUN apk --no-cache add \
   ca-certificates \
   mysql-client \
+  py3-docutils \
   py3-pip
 
 RUN pip3 install --upgrade \
@@ -19,7 +20,4 @@ RUN pip3 install --upgrade \
 RUN pip3 install --no-cache-dir \
   "git+http://github.com/pixelb/crudini.git@0.9.3#egg=crudini" \
 
-# Note(decentral1se): for RST rendering
-RUN pip install py3-docutils
-
 ENTRYPOINT ["/sbin/entrypoint.sh"]