Sub-config used to hold the parameters of a SkyMap.
Notes
-----
This config only needs to exist because we can't put a
`~lsst.pex.config.RegistryField` directly inside a
`~lsst.pex.config.ConfigDictField`.
It needs to have its only field named "skyMap" for compatibility with the
configuration of `lsst.pipe.tasks.MakeSkyMapTask`, which we want so we can
use one config file in an obs package to configure both.
This name leads to unfortunate repetition with the field named
"skymap" that holds it - "skyMap[name].skyMap" - but that seems
unavoidable.
Definition at line 213 of file convertRepo.py.