Update prep_binary_for_pypi.sh

Author: atalman

release/pypi/prep_binary_for_pypi.sh

@@ -82,6 +82,6 @@ for whl_file in "$@"; do
             done
         fi
 
-        zip -qr "${new_whl_file}" .
+        zip -qr9 "${new_whl_file}" .
     )
 done