Browserfetcher class for getting started with puppeter

file ：https://github.com/puppeteer/puppeteer/blob/main/docs/api.md#class-browserfetcher​​​​​​

1. brief introduction

BrowserFetcher You can download and manage different versions of Chromium and Firefox.

BrowserFetcher Specify Chromium The exact version of the revision string

stay Firefox in ,BrowserFetcher download Firefox Nightly And run on the version number , for example "75".

const puppeteer = require("puppeteer");

(async function (){
    const browserFetcher = puppeteer.createBrowserFetcher();
    const canDownload = await browserFetcher.canDownload('533271');
    console.log('can download',canDownload)
    const revisionInfo = await browserFetcher.download('533271');
    const browser = await puppeteer.launch({
        headless: false,
        ex