PyPI downloads shield showing "rate limited by upstream service"

The PyPI Downloads badge seems to fairly often be showing up like this:

I think for other services the cache time was increased to address the issue.

It might also be nice to have an option to tell shields.io to return a 0 width image in case of an error -- since I'm using it in a place where it would be "nice to have" but if it frequently shows an error message than I'd rather just remove it entirely than make users see an error message.