Bump OpenTimelineIO from 7302ff1 to 4b3b673

Bumps [OpenTimelineIO](https://github.com/PixarAnimationStudios/OpenTimelineIO) from `7302ff1` to `4b3b673`.
- [Release notes](https://github.com/PixarAnimationStudios/OpenTimelineIO/releases)
- [Commits](AcademySoftwareFoundation/OpenTimelineIO@7302ff1...4b3b673)

---
updated-dependencies:
- dependency-name: OpenTimelineIO
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>