submodule: bump openthread from `bef3f6e` to `b9ee08d` (#155)
submodule: bump openthread from `bef3f6e` to `b9ee08d` (#155)

Bumps [openthread](https://github.com/openthread/openthread) from `bef3f6e` to `b9ee08d`.
- [Commits](https://github.com/openthread/openthread/compare/bef3f6e024394640ff8065a2862ebc3bc762de00...b9ee08d87b27c2f82974cf943d2eed4e802a6161)

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

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@github.com>

Co-authored-by: dependabot[bot] <1c358da00a777d4e9898c1280ab801e2df165188@users.noreply.github.com>
openthread/ot-b91,openthread/ot-b91