Updating bazelbuild/platforms

Step 1: Make the release

1. Pick a new version number.
2. Prepare a release bug (example).
3. Submit a PR that updates MODULE.bazel and version.bzl to the new version (example).
4. Start a new release draft.
5. Run distro/makerel.sh to locally create the release. This creates a release archive (.tar.gz) on the local machine, emits suggested release notes, and emits instructions for mirroring the archive to htps://mirror.bazel.build.
6. Using the results of the last step, fill out the release draft consistent with previous releases. Add the local platforms-<version>.tar.gz to the draft's Attach binaries by dropping them here or selecting them pane.
7. Click Publish release to release.

Step 2: Register with the Bazel Central Registry

1. Create a PR on https://github.com/bazelbuild/bazel-central-registry with this pattern.
2. source.json‘s integrity field is a base64 encoding of the archives sha256 hash. If you don’t know how to create this directly, the PR presubmit will fail and show the expected hash.
3. When this PR is submitted, the release is done and available in https://bcr.bazel.build.