chore: prepare v2 branch

Author: pi0

.github/workflows/ci.yml

@@ -3,10 +3,10 @@ name: ci
 on:
   push:
     branches:
-      - main
+      - v2
   pull_request:
     branches:
-      - main
+      - v2
 
 jobs:
   lint:

README.md

@@ -9,6 +9,9 @@
 
 Create web servers that run anywhere! 📖 [**documentation**](https://nitro.unjs.io)
 
+> [!NOTE]
+> You are on the v2 branch. Check [main branch](https://github.com/unjs/nitro/tree/main) for v3 development tree.
+
 ## Contribution
 
 <details>