fix: only create versions of records that changed in an upsert - #205

Entity without __spark_metadata__ field is deprecated. Entity AshPaperTrail.Resource.BelongsToActor does not define a `__spark_metadata__` field. This field is required to access source annotations. Add `__spark_metadata__: nil` to the defstruct for AshPaperTrail.Resource.BelongsToActor.