Build(deps): Bump third_party/surelog from 5c96759 to 21f2bc5

Bumps [third_party/surelog](https://github.com/chipsalliance/Surelog) from `5c96759` to `21f2bc5`.
- [Commits](chipsalliance/Surelog@5c96759...21f2bc5)

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

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