build(deps): bump third_party/gflags from 827c769 to 986e8ee (#1823)

Bumps [third_party/gflags](https://github.com/gflags/gflags) from `827c769` to `986e8ee`.
- [Release notes](https://github.com/gflags/gflags/releases)
- [Commits](gflags/gflags@827c769...986e8ee)

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

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>