deps: update url-polyfill dependency

The previous location no longer exists. This is a fork of the original package,
which is actively maintained.

Fixes: #3304

package-lock.json

         "sdp-transform": "2.3.0"
       }
     },
+    "@webcomponents/url": {
+      "version": "0.7.1",
+      "resolved": "https://registry.npmjs.org/@webcomponents/url/-/url-0.7.1.tgz",
+      "integrity": "sha512-9oFDpuZ+tAogjPYQPhNEX86Npzb73A4kv9DOPsSO9aWoWgoevoP6eKx+TKMwO8BJxtTpSM9nKenHQTJ56SP2Cw=="
+    },
     "abbrev": {
       "version": "1.1.1",
       "resolved": "https://registry.npmjs.org/abbrev/-/abbrev-1.1.1.tgz",
         }
       }
     },
-    "url-polyfill": {
-      "version": "github:github/url-polyfill#39734186de44612bc5a16eb25f5407adcc5b2e7c",
-      "from": "github:github/url-polyfill#39734186de44612bc5a16eb25f5407adcc5b2e7c"
-    },
     "use": {
       "version": "3.1.0",
       "resolved": "https://registry.npmjs.org/use/-/use-3.1.0.tgz",

package.json

     "@atlaskit/tabs": "4.0.1",
     "@atlaskit/theme": "2.4.0",
     "@atlaskit/tooltip": "9.1.1",
+    "@webcomponents/url": "0.7.1",
     "autosize": "1.18.13",
     "es6-iterator": "2.0.3",
     "es6-symbol": "3.1.1",
     "redux": "4.0.0",
     "redux-thunk": "2.2.0",
     "styled-components": "1.4.6",
-    "url-polyfill": "github:github/url-polyfill#39734186de44612bc5a16eb25f5407adcc5b2e7c",
     "uuid": "3.1.0",
     "xmldom": "0.1.27"
   },

react/features/base/lib-jitsi-meet/native/polyfills-browser.js

 import Iterator from 'es6-iterator';
 import BackgroundTimer from 'react-native-background-timer';
-import 'url-polyfill'; // Polyfill for URL constructor
+import '@webcomponents/url'; // Polyfill for URL constructor
 
 import { Platform } from '../../react';