Resolving CustomPostUnion to a single type

If there is only one type added to CustomPostUnion (eg: only Post), we can then have the fields that resolve to CustomPostUnion be resolved to that unique type instead.

For that, head over to the Settings page for Schema Custom Posts, and click on option "Use single type instead of union type?":

For instance, if Post is the only type, field customPosts from type Root resolves to it directly:

 field resolves to  type
`customPosts` field resolves to `Post` type