submodule: bump openthread from `2bc87ce` to `5cfbcfc` (#296)
submodule: bump openthread from `2bc87ce` to `5cfbcfc` (#296)

Bumps [openthread](https://github.com/openthread/openthread) from `2bc87ce` to `5cfbcfc`.
- [Commits](https://github.com/openthread/openthread/compare/2bc87ce157e87fc0c98aff18a791cbaa588c37f3...5cfbcfcbf4cbf1e33cdeb00db9b7f8903374c4e2)

---
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-samr21,openthread/ot-samr21