Update README.md before archiving (#362)
diff --git a/README.md b/README.md
index a6a064d..e9b42b7 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,6 @@
+> [!IMPORTANT]
+> This repo has moved to https://github.com/dart-lang/core/tree/main/pkgs/collection
+
[](https://github.com/dart-lang/collection/actions/workflows/ci.yml)
[](https://pub.dev/packages/collection)
[](https://pub.dev/packages/collection/publisher)