Update project authors

Change project authorship to "python-restx Authors"
and update LICENCE/setup.py accordingly to reflect
ownership of the new fork.

LICENSE

@@ -2,6 +2,7 @@ BSD 3-Clause License
 
 Original work Copyright (c) 2013 Twilio, Inc
 Modified work Copyright (c) 2014 Axel Haustant
+Modified work Copyright (c) 2020 python-restx Authors
 
 All rights reserved.
 

setup.py

@@ -72,8 +72,8 @@ def pip(filename):
     description=__description__,
     long_description=long_description,
     url='https://github.com/python-restx/flask-restx',
-    author='Axel Haustant',
-    author_email='axel@data.gouv.fr',
+    author='python-restx Authors',
+    author_email='', # TODO
     packages=find_packages(exclude=['tests', 'tests.*']),
     include_package_data=True,
     install_requires=install_requires,