I need to set a proxy chrome extension to work on only a specifc website

I need your help!

I'm not a profissional, but I'm trying to create a proxy Chrome Extension, and It is working fine! However, I'd like it works only for some specifics website, not for all. Currently, It is working for all website, how could I set it to work only for youtube, google and netflix?

function startProxy() {
  var config = {
    mode: "fixed_servers",
    rules: {
      singleProxy: {
        scheme: "http",
        host:   "IP",       // Proxy IP or URL: type -> string
        port:   80      // Proxy port : type -> int
      },
      bypassList: ["localhost"]
    }
  };
  chrome.proxy.settings.set({value: config, scope: "regular"}, function() {});
}

function callbackFn(details) {
    return {
        authCredentials: {
            username: "USER",
            password: "PW"
        }
    };
}
chrome.webRequest.onAuthRequired.addListener(
            callbackFn,
            {urls: ["<all_urls>"]},
            ['blocking']
);
startProxy();