submodule: bump openthread from `b34f2a3` to `0a74d66` (#233)
submodule: bump openthread from `b34f2a3` to `0a74d66` (#233)

Bumps [openthread](https://github.com/openthread/openthread) from `b34f2a3` to `0a74d66`.
- [Commits](https://github.com/openthread/openthread/compare/b34f2a3fd378e703ce37e4c939940b49dcc56696...0a74d66fedd3c9558ccf298055305a0eef5a6896)

---
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