Avoid pinning versions of dependencies

[dvzrv]

Hi! I'm currently trying to package this for Arch Linux (for packaging pyocd).

When looking at your package requirements, it shows that the requirement on pypemicro is pinned to 0.1.7.
This is problematic in the context of system package management where only one package version is allowed (downstream distributions will remove this strict requirement). Is there a particular reason for it to be there?

Somewhat related: It seems as if the pypemicro project is currently not very transparent about which commit in the project repository let to what release on pypi.org.

Also somewhat related: The information on the requirements in the README are outdated and probably should not be there.