submodule: bump openthread from `3a90ed8` to `814a6c1` (#124)
submodule: bump openthread from `3a90ed8` to `814a6c1` (#124)

Bumps [openthread](https://github.com/openthread/openthread) from `3a90ed8` to `814a6c1`.
- [Commits](https://github.com/openthread/openthread/compare/3a90ed81f0a00761510630162b59f81446df995b...814a6c17effac4e3f5bb7c3ed57166ea748f1cc6)

---
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