prevent installation of newest releases of pillow which break the tests
prevent installation of newest releases of pillow which break the tests

a fix has been written for the Pillow library, but it is not released yet.
https://github.com/python-pillow/Pillow/commit/01e423da00c7039e447a477c21a7414a2ccae5e1

mapproxy/mapproxy,drnextgis/mapproxy,drnextgis/mapproxy,mapproxy/mapproxy