Add configuration for OBS workflow
As requested on https://gitlab.com/openconnect/openconnect/-/merge_requests/342 adding support for the OBS workflow here too.
It will build here (from my branch for now, once I have permissions to set up the tokens on the repo I'll switch over):
https://build.opensuse.org/package/show/home:bluca:openconnect/network-manager-openconnect