[bazel/infra] Add manual BCR release workflow (backport #567)

[mergify]

Internal tooling

Summary

Adds the publish.yaml workflow to release a tag to the Bazel Central Registry (BCR). This workflow uses the official reusable publish-to-bcr workflow from the bazel team.

For now, the workflow must be triggered manually. Once we have iron'ed out any unforeseen issues over a few releases, we can tie it to our release automation.

The following template files are added to mirror the existing files in the latest manual bcr release for gz-sensors.

• .bcr/metadata.template.json
• .bcr/presubmit.yml
• .bcr/source.template.json

Some of the fields are auto-populated by publish-to-bcr based on the repo details when creating a PR in BCR.

Note that MODULE.bazel will be auto-patched by publish-to-bcr to insert the new version based on the tag e.g. tag gz-sensors10_10.0.0 --> version 10.0.0. This version will also be added to metadata.json alongside existing versions.

Testing

This PR mirrors the BCR setup for gz-utils: gazebosim/gz-utils#192. See testing instructions there.

Checklist

• Signed all commits for DCO
• Added tests
• Added example and/or tutorial
• Updated documentation (as needed)
• Updated migration guide (as needed)
• Consider updating Python bindings (if the library has them)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
• While waiting for a review on your PR, please help review another open pull request to support the maintainers
• Was GenAI used to generate this PR? If so, make sure to add "Generated-by" to your commits. (See this policy for more info.)

Note to maintainers: Remember to use Squash-Merge and edit the commit message to match the pull request summary while retaining Signed-off-by and Generated-by messages.

---

This is an automatic backport of pull request #567 done by Mergify.