Update README.md (#5466)

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#### Does this PR need a docs update or release note?

- [ ] ✅ Yes, it's included
- [ ] 🕐 Yes, but in a later PR
- [ ] ⛔ No

#### Type of change

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- [ ] 🌻 Feature
- [ ] 🐛 Bugfix
- [ ] 🗺️ Documentation
- [ ] 🤖 Supportability/Tests
- [ ] 💻 CI/Deployment
- [ ] 🧹 Tech Debt/Cleanup

#### Issue(s)

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#### Test Plan

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- [ ] 💪 Manual
- [ ] ⚡ Unit test
- [ ] 💚 E2E

README.md

@@ -1,3 +1,6 @@
+> [!NOTE] 
+> **The Corso project is no longer actively maintained and has been archived**.
+
 <p align="center">
     <img src="https://github.com/alcionai/corso/blob/main/website/static/img/corso_logo.svg?raw=true" alt="Corso Logo" width="100" />
 </p>

website/package.json

@@ -16,7 +16,7 @@
   "dependencies": {
     "@docusaurus/core": "3.1.1",
     "@docusaurus/plugin-google-gtag": "^3.5.1",
-    "@docusaurus/preset-classic": "3.5.0",
+    "@docusaurus/preset-classic": "3.1.1",
     "@loadable/component": "^5.16.3",
     "@mdx-js/react": "^3.0.0",
     "animate.css": "^4.1.1",