Update release checklist

Author: cwfitzgerald

docs/release-checklist.md

@@ -50,6 +50,7 @@ Day of Release:
 - Create a new tag called `vX.Y.Z` and push it to the repo.
 - Create a new release on the `wgpu` repo with the changelog from this version, targeting that tag
 - Create a branch with the with the new version `vX` and push it to the repo.
+  - On this branch, remove the [!NOTE] at the top of [wgpu/examples/README.md].
 - Complete the release's milestone on GitHub.
 - Create a new milestone for the next release, in 12 weeks time.
 - Update the release checklist with any needed changes.