Added useful tip with local addresses

[zzetao]

You don't have to check my local IP when I want to access it on a device in the same LAN

For example:

npx vite

Running at:
  > http://127.0.0.1:3000
  > http://192.168.1.35:3000

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And, fs.promises in src/server/utils.ts does not support some lower versions of node.

Use util.promisify to support > node 8