[BUG] gpgkey is filtered out by the normalize pkgrepo function for suse

[darix]

the documentation says you can pass the path for the gpgkey but all unknown fields are dropped

https://github.com/openSUSE/salt/blob/openSUSE/release/3006.0/salt/states/pkgrepo.py#L754-L776

please allow all fields from the repo file format to pass through