## Summary

Fix failing `assign-reviewers` workflow — pip's `--hash` syntax only
works in requirements files (`-r`), not constraint files (`-c`). The `-c
/dev/stdin` approach caused: `hashes are missing from some
requirements`.

Failing run:
https://github.com/zed-industries/zed/actions/runs/23272148116/job/67667106308

Coordinator PR:
https://github.com/zed-industries/codeowner-coordinator/pull/84

## Test plan

- [x] Verified locally: good hash installs cleanly, bad hash rejected
- [ ] After merge: verify assign-reviewers workflow passes on next PR

Release Notes:

- N/A