Update defusedxml

Author: pitbulk

setup.py

@@ -38,7 +38,7 @@
     install_requires=[
         'isodate>=0.5.0',
         'xmlsec>=0.6.0',
-        'defusedxml==0.5.0'
+        'defusedxml>=0.5.0'
     ],
     dependency_links=['http://github.com/mehcode/python-xmlsec/tarball/master'],
     extras_require={