Team Forming: PR Auto-rotation Assignments

[sstrubberg]

Acceptance Criteria

• Implement PR Auto-rotation assignments in Github
• Create a program where new hire devs along with dotcom devs feel proficient in reviewing and approve PRs with high quality code.

REF https://github.com/carbon-design-system/carbon/pull/16335

### Tasks
- [x] Create reviewer team
- [x] Turn on PR auto-assign from new team
- [ ] ~Clarify/document expectations for PR review shadowing~