Update release-playbook.md
Added a new requirement for cherry-picks
@@ -65,6 +65,7 @@ While the release is active, you should make sure to do the following:
* If a Bazel team member has proposed the fixes, then proceed with the cherry-pick and merge it.
* If a Bazel team member authors a commit and a community member asks to cherry-pick, then confirm with the author before cherry-picking the PR to make sure this change is safe to merge.
* If a community member author a commit and asks to cherry-pick, then confirm with the reviewer before cherry-picking the PR to make sure that the change is safe to merge.
+ * **Note:** Before merging a change into the release branch, confirm that the original change is already merged at Bazel@HEAD. One simple way to do this is to make sure all cherry-picked commits contain `PiperOrigin-RevId: <CL number>` in the commit message. For some exceptions, if it's really specific to the release branch, include a good description in the PR description and make sure it's signed-off by a Bazel team member.
* Review any PRs sent to the release branch and merge them as necessary.
* Make sure to close any related release blocker issues after merging the PRs; merging PRs into non-main branches does *not* automatically close related issues (see [GitHub docs](https://docs.github.com/en/issues/tracking-your-work-with-issues/linking-a-pull-request-to-an-issue)).
* Before closing a release blocker issue, add a comment indicating how the issue was resolved, for better tracking (e.g. `cherry-picked in #XYZ` - see [this example](https://github.com/bazelbuild/bazel/issues/16629#issuecomment-1302743541))
