Building/installing `pyfastx` from source is not possible due to zlib upgrade

[aroon-color]

We noticed that pyfastx cannot be built currently because it pins the zlib release 1.2.13. This release's zip has been pulled from https://zlib.net/. I've updated the pinned version to 1.3 and can confirm that pyfastx builds as expected and that zlib-based functionality still works.

This + another issue has been addressed in our PR here: https://github.com/color/color/pull/70660