Bump third_party/pybind11/repo from 8b03ffa to 6b92b6e

Bumps [third_party/pybind11/repo](https://github.com/pybind/pybind11) from `8b03ffa` to `6b92b6e`.
- [Release notes](https://github.com/pybind/pybind11/releases)
- [Commits](pybind/pybind11@8b03ffa...6b92b6e)

---
updated-dependencies:
- dependency-name: third_party/pybind11/repo
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>