Update README.md before archiving (#134)
diff --git a/README.md b/README.md
index 332d900..a0733ce 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/fixnum
+
[](https://github.com/dart-lang/fixnum/actions/workflows/test-package.yml)
[](https://pub.dev/packages/fixnum)
[](https://pub.dev/packages/fixnum/publisher)