windows: fix serve-develop with recent pip versions
windows: fix serve-develop with recent pip versions

olt/mapproxy,mapproxy/mapproxy,drnextgis/mapproxy,vrsource/mapproxy,camptocamp/mapproxy,drnextgis/mapproxy,mapproxy/mapproxy,camptocamp/mapproxy,olt/mapproxy,vrsource/mapproxy