submodule: bump openthread from 0b269e1 to 2ce6e95 (#566)

Bumps [openthread](https://github.com/openthread/openthread) from `0b269e1` to `2ce6e95`.
- [Commits](openthread/openthread@0b269e1...2ce6e95)

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>