Fix Markdown requirement
Fix Markdown requirement

Flask-Flatpages does allow newer versions (also 3.x.x) of Markdown, but it is not compatible with Markdown >= 3.x.x
agdsn/sipa,MarauderXtreme/sipa,MarauderXtreme/sipa,agdsn/sipa,MarauderXtreme/sipa,agdsn/sipa,agdsn/sipa