support update services that provide IP auto-detection #76
Description
Currently, we can't update services if no detector is present. This is counter-intuitive, since many dynamic dns services offer some form of fallback automatic IP detection if none was specified. We should support this behaviour. This would also simplify the usage, since there would be one thing less to configure / think about.
If you want support for this, add a "++" comment below - support for additional services will be added on-demand.