Update setup.py

Update url of asset importer lib repo home.

port/PyAssimp/setup.py

@@ -6,7 +6,7 @@ setup(name='pyassimp',
       version='0.1',
       license='ISC',
       description='Python bindings for the Open Asset Import Library (ASSIMP)',
-      url='http://assimp.sourceforge.net/',
+      url='https://github.com/assimp/assimp',
       packages=['pyassimp'],
       data_files=[('share/pyassimp', ['README.md']),
                   ('share/examples/pyassimp', ['scripts/' + f for f in os.listdir('scripts/')])]