Merge pull request #1604 from microsoft/samruddhikhandale/add-note

README: add note

Author: samruddhikhandale

README.md

@@ -1,3 +1,9 @@
+**IMPORTANT NOTE: We're starting to migrate contents of this repo to the [devcontainers org](https://github.com/devcontainers), as part of the work on the [open dev container specification](https://containers.dev).**
+
+**We've currently migrated a set of Features to a new [devcontainers/features](https://github.com/devcontainers/features) repo, and we'll now be publishing images from [devcontainers/images](https://github.com/devcontainers/images).**
+
+**For more details, you can review the [announcement issue](https://github.com/microsoft/vscode-dev-containers/issues/1589).**
+
 # VS Code Remote / GitHub Codespaces Container Definitions
 
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