revert watch change

it isn't needed to enable the file watcher

Author: 43081j

packages/dev-server-hmr/demo/server.config.js

@@ -2,6 +2,5 @@ const { hmrPlugin } = require('../dist/index');
 
 module.exports = {
   rootDir: '.',
-  watch: true,
   plugins: [hmrPlugin()],
 };