[Feature Request] Add support for bzlmod

[Martin-Idel]

Feature description:
Since Bazel switched to using bzlmod (and therefore MODULE.bazel) as the recommended way of dealing with repositories, protovalidate-cc should also support this. In addition, it would be nice to then add the repo into the bazel central registry.

Problem it solves or use case:
Use repository in modern bazel modules.

Contribution:
I can look into it, but I'm not too familiar with that side of Bazel myself, yet.

Examples or references:
protovalidate itself added support recently: https://github.com/bufbuild/protovalidate

[jchadwick-buf]

Quick update here. We would love to add support for Bzlmod in protovalidate-cc. One potential blocker here is a lack of support in some of our dependencies; we'll need to make sure it's still possible for us to adopt bzlmod even if some of our dependencies have not. I have an inkling it might be possible using extensions, but I haven't tried.

We're hoping we can sort this out ahead of the Bazel 9 release later this year, but we don't have an exact timeframe for when this might be resolved; it might be sooner or later.

[jchadwick-buf]

Support for this is about to be added as a part of #88, but it will still not be in the BCR yet, so you'll need to use a bazel_dep + an override rule to consume it for now. We'll probably tackle trying to get this into the BCR next release.