GH codeowner for RN

[marandaneto]

Problem

I have to check every PR to see if there's anything related to RN Allowing empty issues/PRs usually allows low barriers and low-quality descriptions. GH Actions have to be manually upgraded

Changes

RN PRs automatically assigned to me Only allow using PR and Issues templates, blank just for PH people.

Release info Sub-libraries affected

Bump level

• [ ] Major
• [ ] Minor
• [ ] Patch

Libraries affected

• [ ] All of them
• [ ] posthog-web
• [ ] posthog-node
• [ ] posthog-react-native

Changelog notes

• Added support for X