correct package's wheel URL

Author: dimpase

build/pkgs/pythran/checksums.ini

@@ -1,4 +1,4 @@
 tarball=pythran-VERSION-py3-none-any.whl
 sha1=2341d42c014f88318f447083c62e8d3953b04ac2
 sha256=be569cc2817b625ccd2c8f74fa3c93806f245c65fadc282c26a9f546ebd34cfa
-upstream_url=https://files.pythonhosted.org/packages/source/p/pythran/pythran-VERSION-py3-none-any.whl
+upstream_url=https://files.pythonhosted.org/packages/packages/py3/p/pythran/pythran-VERSION-py3-none-any.whl