update setup.py for release

setup.py

 #!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 
-# Copyright 2016 tkwant authors.
+# Copyright 2016-2020 tkwant authors.
 #
 # This file is part of tkwant.  It is subject to the license terms in the file
 # LICENSE.rst found in the top-level directory of this distribution and at
@@ -478,7 +478,7 @@ setup_requirements = (
 )
 
 classifiers = """\
-    Development Status :: 4 - Beta
+    Development Status :: 5 - Production/Stable
     Intended Audience :: Science/Research
     Programming Language :: Python :: 3 :: Only
     Topic :: Scientific/Engineering
@@ -494,7 +494,8 @@ def main():
           author_email='tkwant-authors@kwant-project.org',
           description='Package for time-dependent quantum transport simulations',
           long_description=long_description(),
-          platforms=['Unix', 'Linux'],
+          platforms=['Unix', 'Linux', 'Mac OS-X', 'Windows'],
+          url="https://tkwant.kwant-project.org/",
           license='BSD',
           packages=find_packages('.'),
           cmdclass={'build': tkwant_build,