Force using pnpm in the project

When using npm i or pnpm to install the package, an error will be thrown and the installation will stop.

Update package.json:

{
    "scripts": {
        "preinstall": "npx please-use-pnpm"
    }
}

Note: If you don’t want to see npx: 1 installed successfully, took xxxx seconds, you can use the --quiet option (or -q):

{
  "scripts": {
    "preinstall": "npx -q please-use-pnpm"
  }
}

MIT