Set bazel-contrib registry_fork in publish-to-bcr

@meteorcloudy confirmed the transfer of the repo to the bazel-contrib
org in bazel-contrib#1616. Transfering ownership before publishing the release will
streamline publishing to the Bazel Central Registry by avoiding the need
for a personal bazel-central-registry fork.

Author: mbland

.github/workflows/publish-to-bcr.yml

@@ -28,7 +28,7 @@ jobs:
     with:
       tag_name: ${{ inputs.tag_name }}
       # bazelbuild/bazel-central-registry fork used to open a pull request.
-      registry_fork: simuons/bazel-central-registry
+      registry_fork: bazel-contrib/bazel-central-registry
     permissions:
       attestations: write
       contents: write