Add notice for dependency upgrade timeline (#2513)

Author: angelapwen

CHANGELOG.md

@@ -8,7 +8,7 @@ Note that the only difference between `v2` and `v3` of the CodeQL Action is the
 
 - _Upcoming breaking change_: Add support for using `actions/download-artifact@v4` to programmatically consume CodeQL Action debug artifacts. 
 
-  Starting November 30, 2024, GitHub.com customers will [no longer be able to use `actions/download-artifact@v3`](https://github.blog/changelog/2024-04-16-deprecation-notice-v3-of-the-artifact-actions/). Therefore, to avoid breakage, customers who programmatically download the CodeQL Action debug artifacts should set the `CODEQL_ACTION_ARTIFACT_V4_UPGRADE` environment variable to `true` and bump `actions/download-artifact@v3` to `actions/download-artifact@v4` in their workflows.
+  Starting November 30, 2024, GitHub.com customers will [no longer be able to use `actions/download-artifact@v3`](https://github.blog/changelog/2024-04-16-deprecation-notice-v3-of-the-artifact-actions/). Therefore, to avoid breakage, customers who programmatically download the CodeQL Action debug artifacts should set the `CODEQL_ACTION_ARTIFACT_V4_UPGRADE` environment variable to `true` and bump `actions/download-artifact@v3` to `actions/download-artifact@v4` in their workflows. The CodeQL Action will enable this behavior by default in early November and workflows that have not yet bumped to `actions/download-artifact@v3` to `actions/download-artifact@v4` will begin failing then.
 
   This change is currently unavailable for GitHub Enterprise Server customers, as `actions/upload-artifact@v4` and `actions/download-artifact@v4` are not yet compatible with GHES.