submodule: bump openthread from `1f2a315` to `5bc71b2` (#313)
submodule: bump openthread from `1f2a315` to `5bc71b2` (#313)

Bumps [openthread](https://github.com/openthread/openthread) from `1f2a315` to `5bc71b2`.
- [Commits](https://github.com/openthread/openthread/compare/1f2a315acf67d99abc44600c1546c175c5fabf85...5bc71b2a4fe72a911f7c8088f94e54b2104a2c72)

---
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