Libraries can support different versions for different Python versions. To find out what is the latest supported version the easiest way I know is installing without version constraint and running pip freeze to get the version of the installed library so you can add that to the requirements file.
That is the version of PYthon, not pip the error is probably caused by the python version.
Ps: I added code blocks to your post, please use code formatting next time to help us to understand your question more easily.