add archive message

We haven't been able to keep up with changes to dependabot-script and so we're archiving this repo and pointing the community to use the Dependabot CLI which should be easier to keep operational since we use it for smoke testing and general debugging.

Author: jakecoffman

README.md

@@ -1,3 +1,6 @@
+> [!CAUTION]
+> Using dependabot-script is no longer the preferred way to run a self-hosted version of Dependabot. See the [Example CLI Usage](https://github.com/dependabot/example-cli-usage) repo for how to use the [Dependabot CLI](https://github.com/dependabot/cli) instead for this purpose.
+
 ### _WARNING - Scripts are Currently Broken_
 _We recently refactored the monolithic docker image used within the [Dependabot Core][dependabot-core] library into one-image-per-ecosystem. Unfortunately, that broke the scripts in this repo, and we haven't had time to update them yet. We are aware of the problem and hope to provide a solution soon._