submodule: bump openthread from `56ce8e2` to `afcfb7a` (#182)
submodule: bump openthread from `56ce8e2` to `afcfb7a` (#182)

Bumps [openthread](https://github.com/openthread/openthread) from `56ce8e2` to `afcfb7a`.
- [Commits](https://github.com/openthread/openthread/compare/56ce8e259308399200def7c70e3a6fea461451f0...afcfb7ac007df949e75e05a6818954aecc7851c1)

---
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-nrf528xx,openthread/ot-nrf528xx