fix: mappings/VegCore-VegBIEN.csv: source__modified_date: remapped to pubdate instead of datelastmodified because this is actually metadata for the source itself, rather than for the VegBIEN record of the source
fix: mappings/VegCore-VegBIEN.csv: source__modified_date: remapped to pubdate instead of datelastmodified because this is actually metadata for the source itself, rather than for the VegBIEN record of the source