FEATURE - schema changelog incremental materialization

**Are you a Fivetran customer?**

fivetran made issue, from TR

**Is your feature request related to a problem? Please describe.**

this model doesn't change after data is loaded into it, and it draws from the very hefty `stg_fivetran_log__log` model, so let's make it incremental

**Please indicate the level of urgency and business impact of this request**

**Are you interested in contributing to this package?**

- [x] Yes, I can do this and open a PR for your review.
- [ ] Possibly, but I'm not quite sure how to do this. I'd be happy to do a live coding session with someone to get this work implemented.
- [ ] No, I'd prefer if someone else did this. I don't have the time and/or don't know how to incorporate the changes necessary.