fix url in setup.py

Author: kmaehashi

setup.py

@@ -14,7 +14,7 @@ def _read(filename):
       version='.'.join(str(x) for x in VERSION),
       description='Atwiki Client Library',
       long_description=_read('README.rst'),
-      url='http://github.com/kmaehashi/atwiki-python',
+      url='https://github.com/kmaehashi/atwiki-python',
       author='Kenichi Maehashi',
       author_email='webmaster@kenichimaehashi.com',
       license='MIT',