submodule: bump openthread from `a0c4ede` to `0756d1e` (#290)
submodule: bump openthread from `a0c4ede` to `0756d1e` (#290)

Bumps [openthread](https://github.com/openthread/openthread) from `a0c4ede` to `0756d1e`.
- [Commits](https://github.com/openthread/openthread/compare/a0c4ede86db98120dbb48efd8a9f44d848ca07db...0756d1ea8fee17eba0cdee42a34ea353413a4f99)

---
updated-dependencies:
- dependency-name: openthread
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@github.com>

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@github.com>
Co-authored-by: dependabot[bot] <1c358da00a777d4e9898c1280ab801e2df165188@users.noreply.github.com>
openthread/ot-b91,openthread/ot-b91