notes about immutable packages

images/contributing.md

@@ -32,6 +32,12 @@ It is not immutable, so each workflow run with build and push the same tag. This
 > ***Note*** `GITHIB_TOKEN` is autogenerated by GHA during each workflow execution and use to access the container registry. Due to limitations on this token, the workflow is not able to delete the test package. [Reference](https://docs.github.com/en/rest/packages/packages?apiVersion=2022-11-28#delete-a-package-for-an-organization). Even with GHA having admin to the package, since pakcages live at the ORG level, Github requires ORG level admin permissions to delete a package. Since `GITHUB_TOKEN` is generated and use for workflow run only, it's not possible (or desirable) to grant this access at the ORG level.
 > If it's important to delete this test package, we would need to create a dedicated user PAT, grant Org Admin level and use it in the workflow step to delete the package.
 
+### Immutable Packages
+[Publish immutable action reference](https://github.com/actions/publish-immutable-action/pkgs/container/publish-immutable-action)
+[Immutable Actions reference](https://github.com/features/preview/immutable-actions)
+
+> ***Note*** This ↑ is `Public Preview` as of `12/26/24`
+
 ---
 
 ## Local Machine build and push core images (old depracated method)