submodule: bump openthread from `a662c32` to `126e232` (#72)
submodule: bump openthread from `a662c32` to `126e232` (#72)

Bumps [openthread](https://github.com/openthread/openthread) from `a662c32` to `126e232`.
- [Commits](https://github.com/openthread/openthread/compare/a662c32eb074cc624bf344f810f65f8637a89552...126e232ad556e3a5985fe2f44aae205d83a6faa8)

---
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