submodule: bump openthread from `55af6ce` to `3c260bd` (#192)
submodule: bump openthread from `55af6ce` to `3c260bd` (#192)

Bumps [openthread](https://github.com/openthread/openthread) from `55af6ce` to `3c260bd`.
- [Commits](https://github.com/openthread/openthread/compare/55af6ce2c852b870f7477a2508861830d2a4184e...3c260bd7c7444b9bf446429de3fe46fab09162b3)

---
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-cc13x2-cc26x2,openthread/ot-cc13x2-cc26x2