Pin repoze.sendmail == 4.1

See repoze/repoze.sendmail#31 for detailed information

Author: mete0r

setup.py

@@ -79,7 +79,7 @@ def readfile(path):
     ],
     'package_dir': {'': '.'},
     'install_requires': [
-        'repoze.sendmail',
+        'repoze.sendmail == 4.1',
         'requests',
     ],
     'entry_points': {