Copybara import of the project:

--
2daf4262a1 by Andrii Oriekhov <andriyorehov@gmail.com>:

add GitHub URL for PyPi

COPYBARA_INTEGRATE_REVIEW=https://github.com/protocolbuffers/protobuf/pull/10841 from andriyor:patch-1 2daf4262a1
PiperOrigin-RevId: 487868530

python/setup.py

@@ -439,6 +439,9 @@ if __name__ == '__main__':
       download_url='https://github.com/protocolbuffers/protobuf/releases',
       long_description="Protocol Buffers are Google's data interchange format",
       url='https://developers.google.com/protocol-buffers/',
+      project_urls={
+          'Source': 'https://github.com/protocolbuffers/protobuf',
+      },
       maintainer='protobuf@googlegroups.com',
       maintainer_email='protobuf@googlegroups.com',
       license='BSD-3-Clause',