submodule: bump openthread from `69bfc4b` to `0a6fba3` (#140)
submodule: bump openthread from `69bfc4b` to `0a6fba3` (#140)

Bumps [openthread](https://github.com/openthread/openthread) from `69bfc4b` to `0a6fba3`.
- [Commits](https://github.com/openthread/openthread/compare/69bfc4b1c0b5f6597ce4744d68e501bf063c9ee6...0a6fba303aa78310461b83209a2f959db3456647)

---
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-efr32,openthread/ot-efr32,openthread/ot-efr32