README: add information how to download the dependency (PHP-FineDiff)
README: add information how to download the dependency (PHP-FineDiff)

piratenfraktion-nrw/basisentscheid,piratenfraktion-nrw/basisentscheid,piratenfraktion-nrw/basisentscheid,piratenfraktion-nrw/basisentscheid