submodule: bump openthread from `e708324` to `b8df628` (#202)
submodule: bump openthread from `e708324` to `b8df628` (#202)

Bumps [openthread](https://github.com/openthread/openthread) from `e708324` to `b8df628`.
- [Commits](https://github.com/openthread/openthread/compare/e708324c3189cf3ac2f33bfc2d10c61a43a4df6f...b8df628dfbb03b997a2ed5eb7d3cae1f7decb8ca)

---
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