submodule: bump openthread from `4bd7ab4` to `8069b95` (#259)
submodule: bump openthread from `4bd7ab4` to `8069b95` (#259)

Bumps [openthread](https://github.com/openthread/openthread) from `4bd7ab4` to `8069b95`.
- [Commits](https://github.com/openthread/openthread/compare/4bd7ab4b798728d8267fbc92c0db970e5799d210...8069b958d95a8f9cd7f7da8d1fe65c89c7dea68b)

---
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-cc2538,openthread/ot-cc2538