change url in setup.py to the documentation

Author: basnijholt

setup.py

@@ -48,7 +48,7 @@ def get_version_and_cmdclass(package_name):
     name='adaptive',
     description='Adaptive parallel sampling of mathematical functions',
     version=version,
-    url='https://gitlab.kwant-project.org/qt/adaptive',
+    url='https://adaptive.readthedocs.io/',
     author='Adaptive authors',
     license='BSD',
     classifiers=[