Update project url after github maintainer renaming
Update project url after github maintainer renaming

sirex/datapackage-py,datapackages/datapackage-py,sirex/datapackage-py,datapackages/datapackage-py,okfn/datapackage-py,okfn/datapackage-model-py,okfn/datapackage-py,okfn/datapackage-model-py