build(deps): bump third_party/tools/verible from d0f6c1d to 977b5f5

Bumps [third_party/tools/verible](https://github.com/chipsalliance/verible) from `d0f6c1d` to `977b5f5`.
- [Release notes](https://github.com/chipsalliance/verible/releases)
- [Commits](chipsalliance/verible@d0f6c1d...977b5f5)

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

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