add deprecation notice for chart

charts/README.md

@@ -1,5 +1,9 @@
 # Helm Chart
 
+⚠️ This chart has been moved to https://github.com/redpanda-data/helm-charts/tree/main/charts/kminion . Please install this chart instead. The existing archives are still being hosted here, to not break existing deployments.
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+---
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 This chart is intentionally very light on input validation. The goal was to offer a flexible Helm chart that allows
 users to deploy KMinion the way they want to. Therefore it's very flexible at the cost of less input validation, so that
 you might run into runtime errors for a misconfiguration.