Upgrade pysaml2 dependency to latest v4.4.0

This could finally fix issues with serialization

Author: knaperek

setup.py

@@ -58,7 +58,7 @@ def read(*rnames):
     include_package_data=True,
     zip_safe=False,
     install_requires=[
-        'pysaml2==4.0.5',
+        'pysaml2==4.4.0',
         'defusedxml==0.4.1'
         ],
     )