pythonPackages: Add new hetzner module, v0.2.1.

This is for accessing the Hetzner Robot API (an IPMI-like interface).

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
hetzner-nixops-install: Correct typo in meta attr.

I think it's called maintainerS :-)

Signed-off-by: aszlig <aszlig@redmoonstudios.org>