Docker: add pandoc 2.11

src/.docker_modules/pandoc/2.11/Dockerfile

+FROM alpine:3.13
+MAINTAINER Laurent Modolo
+
+ENV PANDOC_VERSION=2.11
+
+RUN echo "https://dl-cdn.alpinelinux.org/alpine/edge/testing" >> /etc/apk/repositories \
+  && apk update \
+  && apk add pandoc~=${PANDOC_VERSION} make

src/.docker_modules/pandoc/2.11/docker_init.sh

+#!/bin/sh
+docker pull lbmc/pandoc:2.11
+docker build src/.docker_modules/pandoc/2.11 -t 'lbmc/pandoc:2.11'
+docker push lbmc/pandoc:2.11