docs: keep stdio note in README.v2 only

Author: raashish1601

README.md

@@ -123,13 +123,6 @@ Alternatively, for projects using pip for dependencies:
 pip install "mcp[cli]"
 ```
 
-On Windows, add the `stdio` extra if you want `pywin32`-backed Job Object cleanup for subprocesses spawned through `mcp.client.stdio`:
-
-```bash
-uv add "mcp[cli,stdio]"
-pip install "mcp[cli,stdio]"
-```
-
 ### Running the standalone MCP development tools
 
 To run the mcp command with uv: