Need to tweak requirements file to get pulp-cli newer versions

[pedro-psb]

pulp-cli is pinned to version ==0.20.2 in dev_requirements.txt, which makes it a little inconvenient to pull updates/bug-fixes into the development environment.

Edit: I don't know why I did not consider using pulp-cli from host (outside oci-env shell), which works fine. So it's not really a significant inconvenient. Still, it seems odd

I've noticed it was done as part of a bugfix (#130), but it's not clear to me if pinning to that version is really part of the fix.
If it's not, we should unpin it again.

[pedro-psb]

Closed by #149