build(deps): Bump external/benchmark from d99cdd7 to 50ffd3e

Bumps [external/benchmark](https://github.com/google/benchmark) from `d99cdd7` to `50ffd3e`.
- [Release notes](https://github.com/google/benchmark/releases)
- [Commits](google/benchmark@d99cdd7...50ffd3e)

---
updated-dependencies:
- dependency-name: external/benchmark
  dependency-type: direct:production
...

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