New package: py-defusedxml (#13419)

var/spack/repos/builtin/packages/py-defusedxml/package.py

+# Copyright 2013-2019 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+
+from spack import *
+
+
+class PyDefusedxml(PythonPackage):
+    """defusing XML bombs and other exploits"""
+
+    homepage = "https://github.com/tiran/defusedxml"
+    url      = "https://pypi.io/packages/source/d/defusedxml/defusedxml-0.5.0.tar.gz"
+
+    version('0.5.0', sha256='24d7f2f94f7f3cb6061acb215685e5125fbcdc40a857eff9de22518820b0a4f4')
+
+    depends_on('py-setuptools', type='build')