Add `CODEOWNERS` to `bcr-ui`

[albertocavalcante]

I've noticed some stale PRs on this repo (mostly dependency upgrades from Renovate that don't tag anyone).

Since I'd like to see external contributions increase (speaking for myself), I believe it would be beneficial to define a CODEOWNERS file, as it's often difficult to determine who should review PRs. Manually identifying and tagging potential reviewers is inefficient and may not always be accurate.

The documentation for adding a new rule currently suggests this approach (https://bazel-contrib.github.io/SIG-rules-authors/hosting-policy.html#adding-a-repo), but I feel this requirement is missing here.

Thoughts?

@alexeagle @hobofan

[alexeagle]

Yes, we should have a CODEOWNERS file here. I haven't heard from @hobofan in a while - we might need to sign up another maintainer too.

[hobofan]

Yeah, also very much in favor of that. While I'm generally not active in the SIG or the Bazel community in general anymore (due to lack of usage of Bazel in both professional and personal projects + other priorities), I'd still be up to be a passive maintainer for inbound contributions.

Of course having additional maintainers would be optimal, and I'd highly welcome that! However as context: The people qualified in terms of frontend/JS and the BCR have usually been the ones that already bear a lot of other responsibilities, so I can understand that it's hard to find someone on that front.

---

Regarding stale PRs + external contributions: I doubt that a lack of CODEOWNERS file is hindering external contributions (but I'm not here to argue about the general good hygiene of having one). So far it felt that whenever someone wanted to make a contribution, they did so, and I'm usually trying to review them (or at least give a initial response) quickly.

As for the renovate PRs, I've stopped trying to keep up with them on a constant basis, as it's mostly busy-work when not doing active work on the repo, so I usually did a wave of them before starting up active work. In order for them to be fully on auto-pilot we would need to have a proper frontend test setup with e.g. Cypress to prevent rendering/functionality regressions, which in the past would happen on occasion with the renovate PRs.

The current tally of open PRs are:

• 2 by me; stalled by lack of co-maintainer available for reviews (+ me not actively pushing to get them reviewed) <- Those might actually be helped by a CODEOWNERS file + an additional maintainer
• 2 by external contributer; Reviewed and stalled on the external side
• Rest are renovate PRs