Change the settings in the `engines` field of `package.json`

The engines field in package.json specifies fixed versions of Node.js and npm.
ref: https://github.com/line/liff-cli/blob/6493f6410905bf6a304a59f908b909d660468a55/package.json#L26-L29

Fixing these versions is inconvenient for users of LIFF CLI.

```
npm warn EBADENGINE Unsupported engine {
npm warn EBADENGINE package: '@line/liff-cli@0.2.0',
npm warn EBADENGINE required: { node: '22.2.0', npm: '10.7.0' },
npm warn EBADENGINE current: { node: 'v20.18.0', npm: '10.8.2' }
npm warn EBADENGINE }
```

By allowing broader versions, users can use LIFF CLI without warnings or errors.

Start by reading the engines field in package.json and checking the Node.js and npm versions it currently specifies. Broaden those constraints as requested, then run npm install and confirm the EBADENGINE warning is gone.

Written by the indexing model from the issue text.